CMOS Setup Specifications

The CMOS RAM must be configured with information about your system's drives and user-selected options before you can use your computer. The Setup program provided with your system is used to select the options you want to use to start your computer.

Running or Accessing the CMOS Setup Program

If you want to run the BIOS Setup program, you usually have to reboot and press a particular key or key combination during the POST. Normally, the correct key to press is displayed onscreen momentarily during the POST. If it flashes past too quickly to read, try pressing the Pause key on the keyboard when it appears. This freezes the system, allowing you to read the display. Pressing any other key (such as the spacebar) un-pauses the system and allows the POST to continue. The major vendors have standardized the following keystrokes to enter the BIOS Setup in recent systems:

• AMI BIOS. Press Delete during POST.

• Phoenix BIOS (FirstBIOS Pro). Press F2 during POST.

• Award BIOS (FirstBIOS). Press Delete or Ctrl+Alt+Esc during POST.

• Microid Research (MR) BIOS. Press Esc during POST.

If your system does not respond to one of these common keystroke settings, you might have to contact the manufacturer or read the system documentation to find the correct keystrokes.

Some unique ones are as follows:

• IBM Aptiva/Valuepoint or ThinkPad. Press F1 during POST or while powering on the system.

• Toshiba notebook/laptop. Press Esc while powering on the system; then press F1 when prompted.

• Older Phoenix BIOS. Boot to a safe mode DOS command prompt, and then press Ctrl+Alt+Esc or Ctrl+Alt+S.

• Compaq. Press F10 during POST.

After you are at the BIOS Setup main screen, you'll usually find a main menu allowing access to other menus and submenus of different sections or screens. Using the Intel D875PBZ motherboard as an example (one of Intel's recent motherboards), let's go through the menus and submenus of this typical (and popular) motherboard. Although other motherboards might feature slightly different settings, most are very similar.

BIOS Setup Menus

Most modern BIOSs offer a menu bar at the top of the screen when you're in the BIOS Setup that controls navigation through the various primary menus. A typical menu bar offers the choices shown in Table 5.8.

Table 5.8. Typical BIOS Setup Menus

Setup Menu Screen	Description
Maintenance	Specifies the processor speed and clears the setup passwords. This menu is available only in Configure mode, set by a jumper on the board.
Main	Allocates resources for hardware components.
Advanced	Specifies advanced features available through the chipset.
Security	Specifies passwords and security features.
Power	Specifies power management features.
Boot	Specifies boot options and power supply controls.
Exit	Saves or discards changes to the setup program options.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Note

Because most common BIOSs use similar settings, I've chosen the Setup used by modern Intel motherboards as an example in the following tables. Because the BIOS is customized by the motherboard manufacturer, even the same BIOS can offer different options for different boards. The settings covered here will help you get a general idea of the type of settings to expect and how the BIOS Setup settings affect your computer.

Choosing each of these selections takes you to another menu with more choices. The following sections examine all the choices available in a typical motherboard, such as the Intel D875PBZ.

Maintenance Menu

The Maintenance menu is a special menu for setting the processor speed and clearing the setup passwords. Older motherboards used jumpers to configure the processor bus speed (motherboard speed) and processor multiplier. Most newer boards from Intel and others now offer this control via the BIOS Setup rather than moving jumpers. In the case of Intel, one jumper still remains on the board called the configuration jumper, and it must be set to Configure mode for the Maintenance menu to be available.

Setup displays this menu only if the system is set in Configure mode. To set Configure mode, power off the system and move the configuration jumper on the motherboard from Normal to Configure (see Figure 5.6, earlier in this chapter). Because this is the only jumper on a modern Intel board, it is pretty easy to find. When the system is powered back on, the BIOS Setup automatically runs, and you will be able to select the Maintenance menu shown in Table 5.9. After making changes and saving, power off the system and reset the jumper to Normal mode for normal operation.

Table 5.9. Typical Maintenance Menu Settings

Feature	Options	Description
Clear All Passwords	OK (default) Cancel	Clears the user and supervisor passwords
Clear BIOS	OK (default) Cancel	Clears the Wired for Management Boot Integrity Service (BIS) credentials
CPU Stepping Signature	No options	Displays CPU's stepping revision
CPU Microcode Update Revision	No options	Displays CPU's microcode update revision
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Note that most newer Intel processors are designed to allow operation only at or below their rated speeds (a feature called speed locking), whereas others allow higher-than-rated speeds to be selected.

If a user forgets his password, all he has to do is set the configuration jumper, enter the Maintenance menu in BIOS Setup, and use the option provided to clear the password. This function doesn't tell the user what the password was; it simply clears it, allowing a new one to be set if desired. This means the security is only as good as the lock on the system case because anybody who can get to the configuration jumper can clear the password and access the system. This is why most better cases come equipped with locks.

Extended Configuration Submenu

The Extended Configuration submenu on some Intel motherboards has memory setup options similar to those found in the section "Additional Advanced Features," later in this chapter. See this section for details.

Main Menu

The standard CMOS Setup menu dates back to the 286 days, when the complete BIOS Setup consisted of only one menu. In the standard menu, you can set the system clock and record hard disk and floppy drive parameters and the basic video type. Newer BIOSs have more complicated setups with more menus and submenus, so the main menu often is fairly sparse compared to older systems.

The main menu in a modern system reports system information such as the BIOS version, the processor type and speed, the amount of memory, and whether the memory or cache is configured for ECC functionality. The main menu also can be used to set the system date and time.

Table 5.10 shows a typical main menu.

Table 5.10. Typical Main Menu Settings

Feature	Options	Description
BIOS Version		Displays the version of the BIOS.
Processor Type		Displays the processor type.
Hyper-Threading Technology	Enabled (default); Disabled	Enables/disables. Hyper-Threading Technology. This option is present only when a processor that supports Hyper-Threading Technology is installed.
Processor Speed		Displays the processor speed.
System Bus Speed		Displays the system bus speed.
System Memory Speed		Displays the system memory speed.
Cache RAM		Displays the size of the L2 cache.
Total Memory		Displays the total amount of RAM.
Memory Mode		Displays the memory mode (dual channel or single channel).
Memory Channel A Slot 0; Memory Channel A Slot 1; Memory Channel B Slot 0; Memory Channel B Slot 1		Displays the amount and type of RAM in the DIMM sockets.
Memory Configuration	Non-ECC (default); ECC	ECC turns on error reporting if the system and all the memory installed supports ECC. This setting is available only when ECC memory is installed.
Language	English (default); others might be listed	Selects the current default language used by the BIOS.
System Time	Hour:minute:second	Specifies the current time.
System Date	Month/day/year	Specifies the current date.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

ECC stands for error correcting code, which is the use of extra bits on the memory modules to detect and even correct memory errors on-the-fly. For ECC to be enabled, more expensive ECC DIMMs would have to be installed in the system. Note that all DIMMs would need to be ECC versions for this to work; if even one is non-ECC, ECC can't be enabled. For mission-critical systems (such as servers), I recommend purchasing ECC memory and enabling this function because it makes the system more fault tolerant and prevents corrupted data due to soft errors in memory. Random memory errors can occur at the rate of up to 1 bit error per month for every 64256 megabytes installed. ECC ensures that these errors don't creep into your data files, corrupt the system, or cause it to crash.

See "Error Correcting Code," p. 520.

Be sure to check whether your motherboard supports ECC before purchasing ECC memory. You can install ECC memory in a non-ECC-capable board, but the ECC functionality will not be available. Also, make sure you are aware of the memory requirements for your board. Don't try to install more memory than the board supports, and be sure the modules you use meet the specifications required by the board. See the documentation for the motherboard for more information on the type and amount of memory that can be installed.

Most older BIOSs report memory as base and extended memory instead of as a single value. Base memory is typically 640KB and sometimes is called conventional memory. Extended memory is that which is beyond the first megabyte in the system.

You can't change any values in the memory fields; they are only for your information because they are automatically counted up by the system. If the memory count doesn't match what you have installed, a problem has likely occurred with some of the memory: It is defective, is not fully seated or properly installed, or is a type that is incompatible with your system.

Advanced Menu

The Advanced menu is a doorway to submenus for setting advanced features that are available through the motherboard chipset. This part of your BIOS setup is specific to the particular chipset the motherboard uses. Many chipsets are available on the market today, and each has unique features. The chipset setup is designed to enable the user to customize these features and control some of the chipset settings. Table 5.11 shows the typical Advanced submenus available.

Table 5.11. Typical Advanced BIOS Submenus

Submenu	Description
PCI Configuration	Configures the IRQ priority of individual PCI slots
Boot Configuration	Configures Plug and Play, resets PnP configuration data, and configures the NumLock key
Peripheral Configuration	Configures peripheral ports and devices
Drive Configuration	Configures ATA devices
Floppy Configuration	Configures the floppy drive
Event Log Configuration	Configures event logging
Video Configuration	Configures video features
USB Configuration	Configures USB support
Chipset Configuration	Configures advanced chipset features
Fan Control Configuration	Configures fan operation
Hardware Monitoring	Monitors system temperatures, voltages, and fan speeds
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

PCI Configuration Submenu

The PCI Configuration submenu is used to select the IRQ priority of add-on cards plugged into the PCI slots. Auto (the default) should be used to allow the BIOS and operating system to assign IRQs to each slot unless specific PCI cards require unique IRQs. See Table 5.12 for a typical example.

Table 5.12. Typical PCI Configuration Submenu Settings

Feature	Options	Description
PCI Slot 1 IRQ Priority	Auto (default), 3, 5, 9, 10, 11	Allows selection of the IRQ priority for PCI bus connector 1
PCI Slot 2 IRQ Priority	Auto (default), 3, 5, 9, 10, 11	Allows selection of the IRQ priority for PCI bus connector 2
PCI Slot 3 IRQ Priority	Auto (default), 3, 5, 9, 10, 11	Allows selection of the IRQ priority for PCI bus connector 3
PCI Slot 4 IRQ Priority	Auto (default), 3, 5, 9, 10, 11	Allows selection of the IRQ priority for PCI bus connector 4
PCI Slot 5 IRQ Priority	Auto (default), 3, 5, 9, 10, 11	Allows selection of the IRQ priority for PCI bus connector 5
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Additional IRQs might be available if onboard devices such as the serial and parallel ports are disabled.

Boot Configuration Submenu

The options in Table 5.13 configure the system's PnP and keyboard configuration during initial boot.

Table 5.13. Typical Boot Configuration Submenu Settings

Feature	Options	Description
Plug and Play O/S	No (default) Yes	Specifies whether a PnP operating system is being used. No lets the BIOS configure all devices. Yes lets the operating system configure plug-and-play devices. Either setting works with a PnP operating system; however, No must be selected if using a non-PnP OS.
NumLock	On (default) Off	Specifies the power-on state of the NumLock feature on the numeric keypad of the keyboard.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Additional Advanced Features

Many boards differ in the advanced chipset menus. In most cases, unless you know exactly which chipset and what type of memory and other items are found in your system, it is best to leave these settings on Auto. In that case, the modern boards use the configuration ROM found on the DIMM or RIMM memory modules to properly configure the memory settings. In fact, many newer boards no longer allow these settings to be manually adjusted because, in most cases, all that does is lead to trouble in the form of an unstable or a failing system. If you do want to play with these settings, I recommend first finding out exactly which memory modules and chipset you have and contacting the manufacturers of them to get their databooks. The databooks have all the technical information related to those devices.

Table 5.14 lists settings used by a typical motherboard's Chipset Configuration submenu.

Table 5.14. Typical Chipset Configuration Menu

Feature	Options	Description
ISA Enable Bit	Enabled (default) Disabled	When enabled, a PCI-to-PCI bridge recognizes only 16-bit I/O addresses that are not aliases of 10-bit ISA addresses (within the bridge's assigned I/O range). This helps prevent resource conflicts with ISA devices that might be present in the system (such as serial or parallel ports) and allows VGA-compatible address range mapping for ISA devices.
PCI Latency Timer	32 (default) 64 96 128 160 192 224 248	Allows you to control the time (in PCI bus clock cycles) that an agent on the PC bus can hold the bus when another agent has requested the bus.
Burn-In Mode		Selects a submenu used to set Burn-In mode configuration options.
Extended Configuration	Default (default) User-defined	Allows the setting of extended configuration options.
SDRAM Frequency[1]	Auto (default) 266MHz 333MHz[2] 400MHz[3]	Allows an override of the detected memory frequency[4].
SDRAM Timing Control[1]	Auto (default) Manual-Aggressive Manual-User-defined	When Auto is selected, timings are programmed according to the memory detected. Manual-Aggressive selects the most aggressive user-defined timings. Manual-User-defined allows manual override of detected SDRAM settings.
CPC Override	Auto (default) Enabled Disabled	Controls the CPC/1n rule mode. Enabled allows the DRAM controller to attempt chip select assertions in two consecutive common clocks.
SDRAM RAS Active to Precharge[5]	8 7 6 (default) 5	Corresponds to tRAS, or the minimum page open time.
SDRAM CAS# Latency[5]	2.0 2.5 (default) 3.0	Selects the number of clock cycles required to address a column in memory.
SDRAM RAS# to CAS# Delay[5]	4 3 2 (default)	Selects the number of clock cycles between addressing a row and addressing a column.
SDRAM RAS# Precharge[5]	4 3 2 (default)	Selects the length of time required before accessing a new row.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

^[1] This feature is displayed only if Extended Configuration is set to User-defined.

^[2] This option is displayed only if the installed processor has a 533MHz system bus.

^[3] This option is displayed only if the installed processor has an 800MHz system bus.

^[4] If SDRAM Frequency is changed, you must reboot for the change to take effect. After changing this setting and rebooting, the System Memory Speed parameter in the Main menu reflects the new value.

^[5] This feature is normally controlled by the serial presence detect (SPD) ROM in the DIMM and is displayed only if SDRAM Timing Control is set to Manual-User-defined.

Some motherboards might also have advanced chipset options similar to those described in Table 5.15.

Table 5.15. Additional Advanced Chipset Options

Setting	Description
System BIOS Cacheable	Allows caching of the system BIOS ROM at F0000hFFFFFh, resulting in better system performance when 16-bit applications are run. If any program writes to this memory area, a system error can result.
Video BIOS Cacheable	Allows caching of the video BIOS ROM at C0000hC7FFFh, resulting in better video performance when 16-bit applications are run. If any program writes to this memory area, a system error can result.
Video RAM Cacheable (Video Memory Cache Mode)	Selecting Enabled allows caching of the video memory (RAM) at A0000hAFFFFh, resulting in better video performance when 16-bit applications are run. If any program writes to this memory area, a memory access error can result. Uncacheable Speculative Write-Combining (USWC) mode is the same as Enabled on some systems.
8/16 Bit I/O Recovery Time	The I/O recovery mechanism adds bus clock cycles between PCI-originated I/O cycles to the ISA bus. This delay takes place because the PCI bus is so much faster than the ISA bus.
Memory Hole at 15M16M	Places a 1MB empty RAM area between 15MB and 16MB. Older software sometimes would not run with 16MB or more memory in the system; enabling this provides a workaround. This is not normally used.
Passive Release	When Enabled, CPU-to-PCI bus accesses are allowed during passive release. Otherwise, the arbiter accepts only another PCI master access to local DRAM.
Delayed Transaction	The chipset has an embedded 32-bit posted write buffer to support delay transaction cycles. Select Enabled to support compliance with PCI specification version 2.1.

Overclocking/Burn-in Test Features

Many motherboards include features designed to overclock the system, which enables you to set the system to run the CPU bus (and therefore the CPU itself) and possibly other buses at higher-than-normal rated speeds. These settings are especially useful for stress testing a system after initial assembly, which is often called a burn-in test. Table 5.16 shows typical overclock/burn-in test features found in the BIOS Setup.

Table 5.16. Overclocking/Burn-in Test Settings

Feature	Options	Description
Do you wish to continue?	No (default) continue	Enables or disables setting of burn-in (overclocking) mode options. Burn-in Mode is an unsupported overclocking capability for use by system engineers, technicians, or experienced users for validation and test purposes.
Host and I/O Burn-In Mode	Default (default) -2.0% -1.0% +1.0% +2.0% +3.0% +4.0%	Alters the host clock (system bus) and I/O clocks (AGP and PCI) by the percentage selected. If this option is set to anything other than Default, the AGP/PCI Burn-In Mode (shown below) is automatically set to Default.
AGP/PCI Burn-In Mode	Default (default) 63.88/31.94MHz 68.05/34.02MHz 69.44/34.72MHz 70.83/35.41MHz 72.22/36.11MHz 73.60/36.80MHz	The Default settings are 66.66/33.33MHz. Using other settings enables the selection of specific AGP/PCI clock frequencies, but only if the host clock (system bus speed) is not changed. If this option is set to anything other than Default, the Host and I/O Burn-In Mode (shown above) is automatically set to Default.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

These settings can be used to speed up the processor and interconnected buses such as PCI and AGP by a specified percentage. For specifically testing AGP video or PCI adapter cards, some motherboards allow the AGP/PCI bus speed to be set independently of the CPU bus. If you intend to use these settings to speed up a system, beware thatdepending on the specific hardware and software you haverunning faster than default clock speeds can reduce system stability and shorten the useful life of the processor, and it might not be covered under warranty. You also might need to invest in better system cooling to offset the extra heat generated by overclocking your system. If any problems occur, return the settings to the default values.

Peripheral Configuration

The Peripheral Configuration menu is used to configure the devices built into the motherboard, such as serial ports, parallel ports, and built-in audio and USB ports.

Table 5.17 shows a typical Peripheral Configuration menu and choices.

Table 5.17. Typical Peripheral Configuration Menu

Feature	Options	Description
Serial Port A	Auto (default) Disabled Enabled	Configures serial port A. Auto assigns the first free COM port (normally COM 1) I/O address 3F8h and IRQ4.
Base I/O address	3F8h (default) 2F8h 3F8h 2F8h	Specifies the base I/O address for serial port A.
Interrupt	IRQ 4 (default) IRQ 3	Specifies the interrupt for serial port A.
Parallel port	Auto (default) Enabled Disabled	Configures the parallel port. Auto assigns I/O addresses 378h and IRQ7.
Mode	Output Only Bi-directional (default) EPP ECP	Selects the mode for the parallel port. EPP is Extended Parallel Port mode, a high-speed, bidirectional mode. ECP is Enhanced Capabilities Port mode, another high-speed, bidirectional mode.
Base I/O address	378 (default) 278	Specifies the base I/O address for the parallel port.
Interrupt	IRQ 7 (default) IRQ 5	Specifies the interrupt for the parallel port.
DMA	DMA 3 (default) DMA 1	Specifies the DMA channel for the parallel port.
Audio	Enabled (default) Disabled	Enables or disables the onboard audio subsystem.
Onboard LAN	Enabled (default) Disabled	Enables or disables the onboard LAN (network card) device.
An asterisk (*) displayed next to an address indicates a conflict with another device.
(EPP and ECP are IEEE-1284-compliant modes and require the use of an IEEE-1284-compliant printer cable.)
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

I recommend disabling the serial and parallel ports if they are not being used because this frees up those resources for other devices.

ATA Configuration Submenu

The ATA Configuration submenu is for configuring ATA devices, such as hard drives, CD-ROM drives, LS-120 (SuperDisk) drives, tape drives, and so on. Table 5.18 shows the ATA Configuration menu and options for a typical modern motherboard.

Table 5.18. Typical ATA Configuration Menu Settings

Feature	Options	Description
ATA Configuration	Enhanced (default) Disabled Legacy	Enhanced causes all Serial ATA (SATA) and Parallel ATA (PATA) resources to be enabled. Disabled causes all ATA resources to be disabled. Legacy causes up to two ATA channels to be enabled for operating systems that require legacy ATA operation.
Legacy ATA Channels	PATA Pri Only PATA Sec Only PATA Pri and Sec SATA P0/P1 Only SATA P0/P1, PATA Sec SATA P0/P1, PATA Pri	Configures PATA and SATA resources for operating systems that require legacy ATA operation. This feature is present only when the ATA configuration option is set to Legacy.
PCI ATA Bus Master	Enabled (default) Disabled	Enables/disables the use of DMA for hard drive BIOS INT13 reads and writes.
Hard Disk Pre-Delay	Disabled (default) 3 Seconds 6 Seconds 9 Seconds 12 Seconds 15 Seconds 21 Seconds 30 Seconds	Specifies the hard disk drive predelay.
SoftRAID Support	Disabled (default) Enabled	Configures SoftRAID support.
SATA Port-0		Select this to display a submenu (if a device is attached).
SATA Port-1		Select this to display a submenu (if a device is attached).
PATA Primary Master		Select this to display a submenu (if a device is attached).
PATA Primary Slave		Select this to display a submenu (if a device is attached).
PATA Secondary Master		Select this to display a submenu (if a device is attached).
PATA Secondary Slave		Select this to display a submenu (if a device is attached).
PATA = Parallel ATA
SATA = Serial ATA
Pri = Primary
Sec = Secondary
P0 = Serial ATA connector 0
P1 = Serial ATA connector 1
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

The hard disk predelay function is to delay accessing drives that are slow to spin up. Some drives aren't ready when the system begins to look for them during boot, causing the system to display Fixed Disk Failure messages and fail to boot. Setting this delay allows time for the drive to become ready before continuing the boot. Of course, this slows down the boot process, so if your drives don't need this delay, it should be disabled.

ATA Configuration Submenus

These submenus are for configuring each ATA device. Of all the BIOS Setup menus, the hard disk settings are by far the most important. In fact, they are the most important of all the BIOS settings. Most modern motherboards incorporate two ATA controllers that support up to four drives. Most modern BIOSs have an autodetect feature that enables automatic configuration of the drives. If this is available, in most cases you should use it because it will prevent confusion in the future. With the Auto setting, the BIOS sends a special Identify Drive command to the drive, which responds with information about the correct settings. From this, the BIOS can automatically detect the specifications and optimal operating mode of almost all ATA hard drives. When you select Auto for a hard drive, the BIOS redetects the drive specifications during POST, every time the system boots. You could swap drives with the power off, and the system would automatically detect the new drive the next time it was turned on.

In addition to the Auto setting, most older BIOSs offered a standard table of up to 47 drive types with specifically prerecorded parameters. Each defined drive type has a specified number of cylinders, number of heads, write precompensation factor, landing zone, and number of sectors. This often was used many years ago, but it is rarely used today because virtually no drives conform to the parameters on these drive type lists.

Another option is to select a setting called User or User Defined, which is where you can enter the specific drive CHS (Cylinder, Head, and Sector) parameters into the proper fields. These parameters are saved in the CMOS RAM and reloaded every time the system is powered up.

Most BIOSs today offer control over the drive translation settings if the type is set to User and not Auto. Usually, two translation settings are available, called Standard and LBA. Standard or LBA-disabled is used only for drives of 528MB or less, where the maximum number of cylinders, heads, and sectors are 1,024, 16, and 63, respectively. Because most drives today are larger, this setting is rarely used.

LBA (logical block addressing) is used for virtually all ATA drives that are larger than 528MB. Note that systems dating from 1997 and earlier usually are limited to a maximum drive size of 8.4GB unless they have a BIOS upgrade. Systems from 1998 and later usually support drives up to 136.9GB; systems dating from 2002 and beyond usually support drives beyond 137GB (48-bit LBA support), although a BIOS upgrade might be necessary. During drive access, the ATA controller transforms the data address described by sector, head, and cylinder number into a physical block address, significantly improving data transfer rates.

Table 5.19 shows the ATA drive settings found in a typical modern motherboard BIOS.

Table 5.19. Typical ATA Drive Settings

Feature	Options	Description
Drive Installed		Displays the type of drive installed.
Type	Auto (default) User	Specifies the ATA configuration mode for ATA devices. Auto User reads settings from the ATA/ATAPI device. User allows settings to be changed.
Maximum Capacity		Displays the drive capacity.
LBA/Large Mode	Auto (default) Disabled	Displays whether automatic translation mode is enabled for the hard disk.
Block Mode	Auto (default) Disabled	Displays whether automatic multiple sector data transfers are enabled.
PIO Mode	Auto (default) 0 1 2 3 4	Sets the Programmed I/O mode.
DMA Mode	Auto (default) SWDMAx MWDMAx UDMAx	Specifies the DMA mode for the drive. SWDMA = SingleWord DMA; MWDMA = MultiWord DMA; UDMA = Ultra DMA.
SMART	Auto (default) Disabled Enabled	Enables/disables Self-Monitoring, Analysis, and Reporting Technology (SMART). Auto enables SMART if it's supported by the drive.
Cable Detected		Displays the type of cable connected to the Parallel ATA interface: 40-conductor or 80-conductor.
ARMD (ATAPI Removable Media Device) Emulation Type	Floppy	This is displayed only when an LS-120 SuperDisk drive is connected.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Setting the drive type to Auto causes the other values to be automatically configured correctly. I recommend this for virtually all standard system configurations. When set to Auto, the BIOS sends an Identify command to the drive, causing it to report back all the options and features found on that drive. Using this information, the BIOS then automatically configures all the settings on this menu for maximum performance with that drive, including selecting the fastest possible transfer modes and other features.

For hard drives, the only option available other than Auto is User. When set to User, the other choices are made available and are not automatically set. This can be useful for somebody who wants to "play" with these settings, but in most cases, all you will get by doing so is lower performance and possibly even trouble in the form of corrupted data or a nonfunctional drive. User should be used only if a drive was originally prepared with a set of values different from those recognized automatically with the default Auto configuration setting.

Floppy Configuration Submenu

The Floppy Configuration submenu is for configuring the floppy drive and interface. Table 5.20 shows the options in a typical BIOS Setup.

Table 5.20. Typical Diskette Configuration Settings

Feature	Options	Description
Diskette Controller	Enabled (default) Disabled	Disables or enables the integrated diskette controller
Diskette A:	Disabled 360KB, 5 1/4" 1.2MB, 5 1/4" 1.44MB, 3 1/2" (default) 720KB, 3 1/2" 2.88MB, 3 1/2"	Specifies the capacity and physical size of floppy disk drive A:
Diskette Write Protect	Disabled (default) Enabled	Disables or enables write protect for floppy disk drive A:
Settings based on the BIOS used by the Intel D845PEBT2 motherboard. Used by permission of Intel Corporation.

By enabling the write-protect feature, you can disallow writing to floppy disks. This can help prevent the theft of data as well as help to prevent infecting disks with viruses should they be on the system.

Event Logging

The Event Logging menu is for configuring the System Management (SMBIOS) event logging features. SMBIOS is a DMI-compliant method for managing computers on a managed network. DMI stands for Desktop Management Interface, a special protocol that software can use to communicate with the motherboard.

Using SMBIOS, a system administrator can remotely obtain information about a system. Applications such as the LANDesk Client Manager (originally developed by Intel but now sold by LANDesk Software) can use SMBIOS to report the following DMI information:

• BIOS data, such as the BIOS revision level

• System data, such as installed peripherals, serial numbers, and asset tags

• Resource data, such as memory size, cache size, and processor speed

• Dynamic data such as event detection, including event detection and error logging

Table 5.21 shows a typical Event Logging menu in BIOS Setup.

Table 5.21. Typical Event Logging Menu

Feature	Options	Description
Event Log		Indicates whether space is available in the event log
View Event Log	[Enter]	Displays the event log
Clear Event Log	OK (default) Cancel	Clears the event log after rebooting
Event Logging	Enabled (default) Disabled	Enables/disables logging of Desktop Management Interface events
ECC Event Logging	Enabled (default) Disabled	Enables/disables logging of ECC events
Mark Events As Read	OK (default) Cancel	Marks all events as read
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Some motherboards with ECC memory also support log ECC events. I find event logging particularly useful for tracking errors such as ECC errors. Using the View Log feature, you can see whether any errors have been detected (and corrected) by the system.

Video Configuration

The Video Configuration menu is for configuring video features. Table 5.22 shows the functions of this menu in a typical modern motherboard BIOS.

Table 5.22. Typical Video Configuration Menu

Feature	Options	Description
AGP Aperture Size	4MB 8MB 16MB 32MB 64MB (default) 128MB 256MB	Specifies the aperture size for the AGP video controller
Primary Video Adapter	AGP (default) PCI	Selects the type of video card used for the boot display device
Settings based on the BIOS used by the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Other motherboards might also include features such as those shown in Table 5.23.

Table 5.23. Additional Video Configuration Menu Options

Feature	Options	Description
Palette Snooping	Disabled (default) Enabled	Controls the capability of a primary PCI graphics controller to share a common palette with an ISA add-in video card
AGP Hardware Detected	No options	Indicates whether a 1x, 2x, or 4x AGP card is installed; disables onboard graphics subsystem

The most common use of this menu is to change the primary video device. This is useful under Windows 98 and later versions, which support dual-monitor configurations. Using this feature, you can set either the AGP or PCI video card to be the primary boot device.

USB Configuration Submenu

The USB Configuration submenu is used for configuring the USB ports on the system. Table 5.24 shows the functions of this menu in a typical modern motherboard BIOS.

Table 5.24. Typical USB Configuration Menu

Feature	Options	Description
High-Speed USB	Enabled (default) Disabled	Set to Disabled when a USB 2.0 driver is not available
Legacy USB Support	Enabled (default) Disabled	Enables/disables legacy USB support
USB 2.0 Legacy Support	FullSpeed (default) HiSpeed	Configures the USB 2.0 Legacy support: HiSpeed = 480Mbps; FullSpeed = 12Mbps
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Some motherboards that have separate USB 1.1 and USB 2.0 ports might offer additional configuration options.

Legacy USB support means support for USB keyboards and mice. If you are using USB keyboards and mice, you will find that the keyboard is not functional until a USB-aware operating system is loaded.

This can be a problem when running DOS; diagnostics software; or other applications that run outside of USB-aware operating systems, such as Windows 98, Windows Me, Windows XP, and Windows 2000. In that case, you should enable the USB legacy support via this menu.

Even with legacy support disabled, the system still recognizes a USB keyboard and enables it to work during the POST and BIOS Setup. If USB legacy support is disabled (the default on some systems), the system operates as follows:

1. When you power up the computer, USB legacy support is disabled.

2. POST begins.

3. USB legacy support is temporarily enabled by the BIOS. This enables you to use a USB keyboard to enter the setup program or Maintenance mode.

4. POST completes and disables USB legacy support (unless it was set to Enabled while in Setup).

5. The operating system loads. While the operating system is loading, USB keyboards and mice are not recognized. After the operating system loads the USB drivers, the USB devices are recognized.

To install an operating system that supports USB, enable USB legacy support in BIOS Setup and follow the operating system's installation instructions. After the operating system is installed and the USB drivers are configured, USB legacy support is no longer used and the operating system USB drivers take over. However, I recommend that you leave legacy support enabled so the USB keyboard functions in DOS while running self-booting or DOS-based diagnostics or when running other non-USB-aware operating systems.

If USB legacy support is enabled, you shouldn't mix USB and PS/2 port keyboards and mice. For example, don't use a PS/2 keyboard with a USB mouse or a USB keyboard and a PS/2 mouse. Also remember that this legacy support is for keyboards and mice only; it won't work for USB hubs or other USB devices. For devices other than keyboards or mice to work, you need a USB-aware operating system with the appropriate USB drivers.

Fan Control Configuration Submenu

Most systems have one or more chassis fans to help cool the system. Table 5.25 shows the function of the Fan Control Configuration submenu on a typical high-performance PC.

Table 5.25. Fan Control Configuration Submenu

Feature	Options	Description
Fan Control	Enabled (default) Disabled	Enables or disables fan control.
Lowest Fan Speed	Slow (default) Off	Defines the lower limit of chassis fan speed operation. When set to Slow, at low system temperatures the fans will continue o run at slow speed. When set to Off, at low system temperatures the fans will turn off.
These options do not take effect until AC power has been completely removed from the system. After saving the BIOS settings and turning off the system, unplug the power cord from the system and wait at least 30 seconds before reapplying power and turning the system back on.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Many newer boards have built-in monitor chips that can read temperature, voltage, and fan speeds. Those that do often include a screen in the BIOS Setup that allows you to view the readings from the monitor chip. Usually such boards also include a hardware monitor program that runs under Windows for more convenient monitoring while the system is in use (see Table 5.26).

Table 5.26. Hardware Monitoring Display

Feature	Description
Processor Zone Temperature	Displays temperature near the CPU in Celsius and Fahrenheit
System Zone 1 Temperature	Displays temperature of Zone 1 in Celsius and Fahrenheit
System Zone 2 Temperature	Displays temperature of Zone 2 in Celsius and Fahrenheit
Processor Fan Speed	Displays CPU fan speed in RPM
Rear Fan Speed	Displays chassis rear fan speed in RPM
Front Fan Speed	Displays chassis front fan speed in RPM
Voltage Regulator Fan Speed	Displays VR fan speed in RPM
+1.5V in	Displays voltage level of +1.5V supply
Vccp	Displays voltage level of CPU core supply
+3.3V in	Displays voltage level of +3.3V supply
+5V in	Displays voltage level of +5V supply
+12V in	Displays voltage level of +12V supply
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Resource Configuration/PnP Configuration Menu

If you have a motherboard with one or more ISA slots, you need to use the Resource Configuration or PnP Configuration menu to determine which IRQs and memory addresses are available for ISA devices. This is not necessary on motherboards that have only PCI or PCI and AGP slots. For more information about this menu, see Upgrading and Repairing PCs, 12th Edition, included in electronic form on the DVD packaged with this book.

Security Menu

Most BIOSs include two passwords for security, called the supervisor and user passwords. These passwords help control who is allowed to access the BIOS Setup program and who is allowed to boot the computer. The supervisor password is also called a setup password because it controls access to the setup program. The user password is also called a system password because it controls access to the entire system.

If a supervisor password is set, a password prompt is displayed when an attempt is made to enter the BIOS Setup menus. When entered correctly, the supervisor password gives unrestricted access to view and change all the Setup options in the Setup program. If the supervisor password is not entered or is entered incorrectly, access to view and change Setup options in the Setup program is restricted.

If the user password is set, the password prompt is displayed before the computer boots up. The password must be entered correctly before the system is allowed to boot. Note that if only the supervisor password is set, the computer boots without asking for a password because the supervisor password controls access only to the BIOS Setup menus. If both passwords are set, the password prompt is displayed at boot time, and either the user or the supervisor password can be entered to boot the computer. In most systems, the password can be up to seven or eight characters long.

If you forget the password, most systems have a jumper on the board that allows all passwords to be cleared. This means that for most systems, the password security also requires that the system case be locked to prevent users from opening the cover and accessing the password-clear jumper. This jumper is often not labeled on the board for security reasons, but it can be found in the motherboard or system documentation.

Provided you know the password and can get into the BIOS Setup, a password can also be cleared by entering the BIOS Setup and selecting the Clear Password function. If no Clear function is available, you can still clear the password by selecting the Set Password function and pressing Enter (for no password) at the prompts.

Table 5.27 shows the security functions in a typical BIOS Setup.

Table 5.27. Typical Security Settings

Feature	Options	Description
Supervisor Password		Reports if a supervisor password is set.
User Password		Reports if a user password is set.
Set Supervisor Password[1]		Specifies the supervisor password.
User Access Level[2]	Full (default) No Access View Only Limited	Sets the user access rights to the BIOS Setup Utility. Full allows the user to change all fields except the supervisor password. No Access prevents user access to the BIOS Setup Utility. View Only allows the user to view but not change the BIOS Setup Utility fields. Limited allows the user to change some fields.
Set User Password[1]		Specifies the user password.
Clear User Password[7]	OK (default) Cancel	Clears the user password.
Chassis Intrusion	Disabled (default) Log Log, notify once Log, notify until cleared	Disabled disables chassis intrusion; Log logs the intrusion in the event log. Log, notify once halts the system during POST, the user must press F4 to continue, the intrusion flag is cleared, and the event log is updated. Log, notify until cleared halts the system during POST and the user must enter the BIOS Setup Security menu and select Clear Chassis Intrusion Status to clear the chassis intrusion flag.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

^[1] Passwords can be up to seven alphanumeric characters, including AZ, az, and 19.

^[2] This feature is displayed only if a supervisor password has been set.

^[7] This feature is displayed only if a user password has been set.

To clear passwords if the password is forgotten, most motherboards have a password-clear jumper or switch. Intel motherboards require that you set the configuration jumper, enter the Maintenance menu in BIOS Setup, and select the Clear Password feature. If you can't find the documentation for your board and aren't sure how to clear the passwords, you can try removing the battery for 15 minutes or soit clears the CMOS RAM. It can take that long for the CMOS RAM to clear on some systems because they have capacitors in the circuit that retain a charge. Note that this also erases all other BIOS settings, including the hard disk settings, so they should be recorded beforehand.

Power Menu

Power management is defined as the capability of the system to automatically enter power-conserving modes during periods of inactivity. Two main classes of power management exist; the original standard was called Advanced Power Management (APM) and was supported by most systems since the 386 and 486 processors. More recently, a new type of power management called Advanced Configuration and Power Interface (ACPI) has been developed and began appearing in systems during 1998. Most systems sold in 1998 or later support the more advanced ACPI type of power management. In APM, the hardware does the actual power management, and the operating system or other software had little control. With ACPI, the power management is now done by the operating system and BIOS, and not the hardware. This makes the control more centralized and easier to access and enables applications to work with the power management. Instead of using the BIOS Setup options, you merely ensure that ACPI is enabled in the BIOS Setup and then manage all the power settings through Windows 98/Me, 2000/XP, or later.

Tables 5.28 and 5.29 show the typical power settings found in a managed system.

Table 5.28. Typical Power Settings for a Managed System

Feature	Options	Description
ACPI		Selects a submenu that sets the ACPI power management options.
After Power Failure	Last State (default) Stay Off Power On	Specifies the mode of operation if an AC power loss occurs. Last State restores the computer to the power state it was in before the power loss. Stay Off keeps the computer powered off until the power button is pressed. Power On boots the computer when power is restored.
Wake on PCI PME	Stay Off (default) Power On	Specifies how the computer responds when system power is off and a PCI power management event occurs.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

Table 5.29. ACPI Submenu

Feature	Options	Description
ACPI Suspend State	S3 State (default) S1 State	S3 consumes less power, but some drivers might not support this state. S1 is the safest mode but consumes more power.
Wake on LAN from S5	Stay Off (default) Power On	In ACPI stay-off mode only, it determines how the system responds to a LAN wake-up event.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

When in Standby mode, the BIOS reduces power consumption by spinning down hard drives and reducing power to or turning off monitors that comply with Video Electronics Standards Organization (VESA) and Display Power Management Signaling (DPMS). While in Standby mode, the system can still respond to external interrupts, such as those from keyboards, mice, fax/modems, or network adapters. For example, any keyboard or mouse activity brings the system out of Standby mode and immediately restores power to the monitor.

In most systems, the operating system takes over most of the power management settings, and in some cases, it can even override the BIOS settings. This is definitely true if the operating system and motherboard both support ACPI.

Some systems feature additional power management settings in their BIOS. These options are listed in "Additional Power Management Settings" in the Technical Reference section of the DVD packaged with this book.

Boot Menu (Boot Sequence, Order)

The Boot menu is used for setting the boot features and the boot sequence (through submenus). If your operating system includes a bootable CDWindows XP, for exampleuse this menu to change the boot drive order to check your CD before your hard drive. Table 5.30 shows the functions and settings available on a typical motherboard.

Table 5.30. Typical Boot Menu Settings

Feature	Options	Description
Silent Boot	Enabled (default) Disabled	Enabled displays the OEM graphic instead of POST messages. Disabled displays normal POST messages.
Add-On ROM Display Mode	Enabled (default) Disabled	Enables/disables the splash screen for add-in cards.
Intel Rapid BIOS Boot	Enabled (default) Disabled	Enables the computer to boot with or without running certain POST tests.
PXE Boot to LAN	Disabled (default) Enabled	Disables/enables PXE boot from LAN. When set to Enabled, you must reboot for the Intel Boot Agent device to be available in the boot Device menu.
USB Boot	Enabled (default) Disabled	Enables/disables booting from USB devices.
Boot Device Priority		Selects a submenu that specifies the boot sequence from the available types of boot devices.
Hard Disk Drives[*]		Selects a submenu that specifies the boot sequence from the available hard disk drives.
Removable Devices[*]		Selects a submenu that specifies the boot sequence from the available removable devices.
ATAPI CD-ROM Drives[*]		Selects a submenu that specifies the boot sequence from the available ATAPI CD-ROM drives.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

^[*] This feature is displayed only if this type of device is present.

Using this menu, you can configure which devices your system boots from and in which order the devices are sequenced. From this menu, you also can access Hard Drive and Removable Devices submenus, which enable you to configure the ordering of these devices in the boot sequence. For example, you can set hard drives to be the first boot choice, and then in the hard drive submenu, decide to boot from the secondary drive first and the primary drive second. Normally, the default with two drives would be the other way around.

Some recent systems also enable you to boot from external USB drives, such as Zip or LS-120 SuperDisk drives.

Boot Device Priority Submenu

This submenu is used to select the order in which boot devices will be read to start the system. Table 5.31 shows the options found on a typical motherboard.

Table 5.31. Boot Device Priority Submenu

Feature	Options	Description
1st Boot Device 2nd Boot Device 3rd Boot Device 4th Boot Device	Removable (Floppy) Hard Drive device ATAPI CD-ROM device Disabled	Specifies the boot sequence according to the device type. The default settings for the first through fourth boot devices are: 1. Removable, 2. Hard Drive, 3. ATAPI CD-ROM, 4. Disabled
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.
If more than four boot devices are available, they are also displayed in this submenu.

The Hard Disk Drives submenu (not shown) for the D875PBZ motherboard lists up to 12 hard disks, enabling you to choose the preferred boot device; older systems usually list only primary and secondary master and slave (four) drives. This BIOS option enables you to install more than 1 bootable hard disk in your computer and select which one you want to boot from at a BIOS level, rather than by using a boot manager program. If you need to work with multiple operating systems, this menu can be very useful.

The Removable Devices and ATAPI CD-ROM Drives submenus (not shown) list up to four devices of each type, enabling you to select from which removable device or ATAPI drive to boot. On older systems, these options might be included in the boot sequence menu. Some motherboards also list Zip and SCSI drives as bootable drives.

Exit Menu

The Exit menu is for exiting the Setup program, saving changes, and loading and saving defaults. Table 5.32 shows the typical selections found in most motherboard BIOSs.

Table 5.32. Typical Exit Menu Settings

Feature	Description
Exit Saving Changes	Exits and saves the changes in CMOS RAM.
Exit Discarding Changes	Exits without saving any changes made in the BIOS Setup.
Load Optimal Defaults	Loads the factory (optimal) default values for all the Setup options.
Load Custom Defaults	Loads the custom defaults for Setup options.
Save Custom Defaults	Saves the current values as custom defaults in CMOS RAM. Normally, the BIOS reads the saved Setup values from CMOS RAM. If this memory is corrupted, the BIOS reads the custom defaults. If no custom defaults are set, the BIOS reads the factory defaults from the flash ROM.
Discard Changes	Discards changes without exiting Setup. The option values present when the computer was turned on are used.
Settings based on the BIOS used in the Intel D875PBZ motherboard. Used by permission of Intel Corporation.

After you have selected an optimum set of BIOS Setup settings, you can save them using the Save Custom Defaults option. This enables you to quickly restore your settings if they are corrupted or lost. All BIOS settings are stored in the CMOS RAM memory, which is powered by a battery attached to the motherboard.

Additional BIOS Setup Features

Some systems have additional features in their BIOS Setup screens, which might not be found in all BIOSs. Some of the more common features you might see are listed in Table 5.33.

Table 5.33. Additional BIOS Setup Features

Feature	Description
CPU Hyper-threading	Displayed on motherboards designed for use with the Intel Pentium 4 3.06GHz and faster processors with HT Technology when such processors are installed. When enabled, this feature enables hyper-threading for faster performance when multiple applications are running.
PC Health (menu)	This menu can display information such as CPU Vcore; 3.3V, 5V, and 12V actual voltage values; chassis and processor temperature; and fan speeds. The information can be used by system management programs to warn you of problems or shut down the computer automatically.
Serial ATA Controller	When enabled, Serial ATA (SATA) drives can be used.
IEEE-1394a Port	When enabled, you can use IEEE-1394a ports for DV camcorders, external hard drives, and other IEEE-1394a devices.
ATA RAID Controller	When enabled, additional ATA ports provided for RAID or individual ATA drives can be used.
Virus Warning	When enabled, you receive a warning message if a program attempts to write to the boot sector or the partition table of the hard disk drive. If you get this warning during normal operation, you should run an antivirus program to see whether an infection has occurred. This feature protects only the master boot sector, not the entire hard drive. Note that programs that usually write to the master boot sector, such as FDISK, can trigger the virus warning message.
CPU Internal Cache/External Cache	This allows you to disable the L1 (internal) and L2 (external) CPU caches. This is often used when testing memory, in which case you don't want the cache functioning. For normal operation, both caches should be enabled.
Quick Power On Self Test	When enabled, this reduces the amount of time required to run the POST. A quick POST skips certain steps, such as the memory test. If you trust your system, you can enable the quick POST, but in most cases I recommend leaving it disabled so you get the full-length POST version.
Swap Floppy Drive	This field is functional only in systems with two floppy drives. Selecting Enabled assigns physical drive B: to logical drive A: and physical drive A: to logical drive B:.
Boot Up Floppy Seek	When enabled, the BIOS tests (seeks) floppy drives to determine whether they have 40 or 80 tracks. Only 360KB floppy drives have 40 tracks; drives with 720KB, 1.2MB, and 1.44MB capacity all have 80 tracks. Because very few modern PCs have 40-track floppy drives, you can disable this function to save time.
Boot Up System Speed	Select High to boot at the default CPU speed; select Low to boot at a simulated 8MHz speed. The 8MHz option often was used in the past with certain copy-protected programs, which would fail the protection scheme if booted at full speed. This option is not used today.
Gate A20 Option	Gate A20 refers to the way the system addresses memory above 1MB (extended memory). When set to Fast, the system chipset controls Gate A20. When set to Normal, a pin in the keyboard controller controls Gate A20. Setting Gate A20 to Fast improves system speed, particularly with protected-mode operating systems such as Windows 9x and Windows 2000/XP.
Typematic Rate Setting	When disabled, the following two items (Typematic Rate and Typematic Delay) are irrelevant. Keystrokes repeat at a rate determined by the keyboard controller in your system. When enabled, you can select a typematic rate and typematic delay.
Typematic Rate (Chars/Sec)	When the typematic rate setting is enabled, you can select a typematic rate (the rate at which characters repeat when you hold down a key) of 6, 8, 10, 12, 15, 20, 24, or 30 characters per second.
Typematic Delay (Msec)	When the typematic rate setting is enabled, you can select a typematic delay (the delay before key strokes begin to repeat) of 250, 500, 750, or 1,000 milliseconds.
Security Option	If you have set a password, select whether the password is required every time the system boots or only when you enter Setup.
PS/2 Mouse Function Control	If your system has a PS/2 (motherboard) mouse port and you install a serial or USB pointing device, select Disabled.
HDD SMART Capability	SMART is an acronym for Self-Monitoring Analysis and Reporting Technology system. SMART is a hard drive self-diagnostic feature available on some ATA hard drives. Enabling this option is recommended if you use diagnostic software that can monitor SMART-compatible drives to warn you of impending failures.
Report No FDD for WIN 95	Select Yes to release IRQ6 when the system contains no floppy drive, for compatibility with Windows 95 logo certification. In the Integrated Peripherals screen, select Disabled or the Onboard FDC Controller field.
ROM Shadowing	ROM chips typically are very slow, around 150ns (nanoseconds), and operate only 8 bits at a time, whereas RAM runs 60ns or even 10ns or less and is either 32 bits or 64 bits wide in most systems. Shadowing is the copying of BIOS code from ROM into RAM, where the CPU can read the BIOS drivers at the higher speed of RAM.
Operating Frequency	Some motherboards enable you to select the FSB (front-side bus) and CPU clock multiilier speeds within the BIOS rather than through the normal motherboard-based DIP switches or jumper blocks. Select this option to enable customized settings for the CPU Clock Multiplier and CPU Frequency options.
CPU Frequency	This option enables you to vary the CPU FSB frequency from the default 66MHz, 100MHz, or 133MHz to higher values, enabling you to overclock your system.
CPU Clock Multiplier	This option enables you to vary the CPU clock multiplier from its default values to higher values if the CPU is not multiplier-locked. Recent and current Intel CPUs ignore nonstandard CPU clock multiplier settings, but AMD Athlon and Duron CPUs can be oveclocked with this option.
CPU Vcore Setting	This option enables you to vary the core voltage of the CPU to improve the stability of your system during overclocking or to install CPUs not specifically supported by the default Automatic voltage settings.