Third-Party Pentium 4 Chipsets

SiS, the ALi Corporation, ATI, and VIA all produce chipsets for the Intel Pentium 4 and Celeron 4 processors.

Although Intel's chipsets for the Pentium 4 have dominated the market up to this point, many of these chipsets offer unique features that are worth considering. The following sections discuss these chipsets by vendor.

SiS Chipsets for Pentium 4 and Pentium D

SiS offers several chipsets for the Pentium 4 and Pentium D, including integrated chipsets, chipsets for use with discrete video accelerator cards, and some that support Rambus RDRAM. Details of SiS's chipsets for the Pentium 4 are available in Tables 4.3235; chipsets for the Pentium D are listed in Tables 4.34 and 4.36. Unlike most of the chipsets SiS has created for the Pentium II/III/Celeron, the SiS chipsets for the Pentium 4 and Pentium D use one of several high-speed South Bridge equivalents (SiS 96x series Media I/O chips) instead of integrating North and South Bridge functions into a single chip. SiS North and South Bridge chips for the Pentium 4 and Pentium D use a high-speed 16-bit connection known as MuTIOL (Multi-Threaded I/O Link) instead of the slow PCI bus as with older chipsets.

Table 4.32. SiS North Bridge Chips for Pentium 4 Socket 478 (up to 533MHz Processor Bus Speed)

Chipset	SiS650	SiS651	SiS645	SiS645DX	SiS648	SiS655	SiS R658	SiS 661GX
Bus speed	400MHz	400/533MHz	400MHz	400/533MHz	400/533MHz	400/533MHz	400/533MHz	400/533MHz
Supports Hyper-Threading	No	Yes[*]	No	Yes[*]	Yes[*]	Yes[*]	Yes[*]	Yes
SMP (dual CPUs)	No	No	No	No	No	No	No	No
Memory types	PC133, DDR266	PC100/133, DDR200/266/333	PC133, DDR200/266	PC133, DDR266/333	DDR200/266/333	DDR266/333, dual-channel	1066/800MHz RDRAM	DDR400/333/266
Parity/ECC	Neither	Neither	Neither	Neither	Neither	Neither	Neither	Neither
Maximum memory 3GB	3GB	3GB	3GB	3GB	4GB	4GB	3GB
PCI support	2.2	2.2	2.2	2.2	[^]	[^]	[^]	[^]
PCI speed/width	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit
AGP slot	4x	4x	4x	4x	8x	8x	8x	8x
Integrated video	Yes	Yes	No	No	No	No	No	Mirage DirectX 7.0, 64MB
South Bridge	SiS961	SiS962	SiS961	SiS961	SiS963, 964 series	SiS963, 964 series	SiS963, 964 series	SiS963, 964 series
MuTIOL speed	533MBps	533MBps	533MBps	533MBps	1GBps	1GBps	1GBps	1GBps

^[*] B-stepping only

^{[^]} PCI 2.2 with SiS963 series, PCI 2.3 with SiS964 series

Table 4.33 lists the SiS North Bridge chips for Pentium 4 processors with 800MHz FSB.

Table 4.33. SiS North Bridge Chips for Pentium 4 (800MHz Processor Bus Speed)

Chipset	SiS648FX	SiS655FX	SiS655TX	SiS656	SiS R659	SiS661FX
Bus speed	800/533/400MHz	800/533/400MHz	800/533/400MHz	800/533/400MHz	800/400/533MHz	800/400/533MHz
Supports Hyper-Threading	Yes	Yes	Yes	Yes	Yes	Yes
SMP (dual CPUs)	No	No	No	No	No	No
Memory types	DDR400/333	Dual-channel DDR400/333	Dual-channel DDR400/333	Dual-channel DDR400/333, DDR-II	Quad-channel RDRAM PC1200	DDR400/222/266
Parity/ECC	Neither	Neither	Neither	ECC	ECC	Neither
Maximum memory	3GB	3GB	4GB	4GB	4GB	3GB
PCI support	2.3	2.3	2.3	2.3	2.3	2.3
PCI speed/width	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit
Video slot	AGP 8x	AGP 8x	AGP 8x	PCI-Express x16	AGP 8x	AGP 8x
Integrated video	No	No	No	No	No	SiS Mirage Graphics 32/64MB
South Bridge	SiS963L	SiS964/964L	SiS964/964L	SiS965/965L	SiS964/964L	SiS964/964L
MuTIOL speed	1GBps	1GBps	1GBps	1GBps	1GBps	1GBps

Table 4.34 lists the SiS North Bridge chips that support the dual-core Pentium D as well as Socket 775 Pentium 4 processors.

Table 4.34. SiS North Bridge Chips for Pentium D and Pentium 4 (Socket 775)

Chipset	SiS649	SiS649FX	SiS656	SiS656FX	SiS661FX
Bus speed	800/533/400MHz	1066MHz	800/533/400MHz	1066/800/533/400MHz	800/400/533MHz
Supports Hyper-Threading	Yes	Yes	Yes	Yes	Yes
SMP (dual CPUs)	No	No	No	No	No
Memory types	Single-channel DDR2 533/400, DDR 400/222/266	Single-channel DDR2 667, DDR 400	Dual-channel DDR2 667/533/400	Dual-channel DDR2 667/533/400	Single-channel DDR400/222/266
Parity/ECC	Neither	Neither	ECC	ECC	Neither
Maximum memory	2GB	2GB	4GB	4GB	3GB
PCI support	2.3	2.3	2.3	2.3	2.3
PCI speed/width	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit
Video slot	PCI Express x16	PCI Express x16	PCI-Express x16	PCI-Express x16	AGP 8x
Integrated video	No	No	No	No	SiS Mirage Graphics 64MB
South Bridge	SiS965, 966 series	SiS965, 966 series	SiS965, 966 series	SiS965, 966 series	SiS964/964L
MuTIOL speed	1GBps	1GBps	1GBps	1GBps	1GBps

Table 4.35 lists the SiS Media I/O (South Bridge) chips referenced in Tables 4.3234.

Table 4.35. SiS Media I/O (South Bridge) Chips for Intel and AMD Processors

South Bridge Chip	USB Support	Number of USB Ports	ATA Support	# of SATA Ports	RAID Levels Supported	Audio	10/100 Ethernet	Gigabit Ethernet	HomePNA 1.0/2.0	IEEE 1394	PCI-Express x1	MuTIOL Throughput
SiS961	1.1	6	33/66/100			AC'97 2.2, 5.1 channel	Yes	No	Yes	No	No	533MBps
SiS961B	1.1	6	33/66/100/133			AC'97 2.2, 5.1 channel	Yes	No	Yes	No	No	533MBps
SiS962	1.1, 2.0	6	33/66/100/133			AC'97 2.2, 5.1 channel	Yes	No	Yes	Yes	No	533MBps
SiS962L	1.1, 2.0	6	33/66/100/133			AC'97 2.2, 5.1 channel	Yes	No	Yes	No	No	533MBps
SiS963	1.1, 2.0	6	33/66/100/133			AC'97 2.2, 5.1 channel	Yes	No	Yes	Yes	No	533MBps
SiS963L	1.1, 2.0	6	33/66/100/133			AC'97 2.2, 5.1 channel	Yes	No	Yes	No	No	533MBps
SiS964	1.1, 2.0	8	33/66/100/133	2	0, 1, JBOD	AC'97 2.3, 5.1 channel	Yes	No	Yes	No	No	1GBps
SiS964L	1.1, 2.0	8	33/66/100/133			AC'97 2.3, 5.1 channel	Yes	No	Yes	No	No	1GBps
SiS965	1.1, 2.0	8	33/66/100/133	4	0, 1, 0+1, JBOD	AC'97, 7.1 channel	Yes	Yes	Yes	No	Yes	1GBps
SiS965L	1.1, 2.0	8	33/66/100/133	2	0, 1, JBOD	AC'97, 7.1 channel	Yes	No	Yes	No	Yes	1GBps
SiS966	1.1, 2.0	8	33/66/100/133	4[*]	0, 1, 0+1, JBOD	AC'97, 7.1 channel HDA	Yes	Yes	Yes	No	Yes	1GBps
SiS966L	1.1, 2.0	8	33/66/100/133	2	0, 1, JBOD	AC'97, 7.1 channel HDA	Yes	No	Yes	No	Yes	1GBps
HDA = High-definition audio
JBOD = Just a bunch of disks (spans all drives into a single logical unit)

^[*] Two ports support AHCI

SiS650/651 Chipsets

The SiS650 and 651 chipsets enable Pentium 4 system builders to create low-cost systems with onboard video that can be enhanced with AGP 4x video cards at a later date. The integrated video features support for high-quality DVD playback and the optional SiS301B video bridge for TV-out and DVI LCD panels.

Both chipsets also feature SiS's own MuTIOL technology for connecting the North Bridge and South Bridge chips with a three-layer high-speed (266MHz/533MBps bandwidth) data highway.

The 650 and 651 both support SDRAM and DDR SDRAM, and the 651 adds support for DDR333 memory, the 533MHz system bus of the latest Pentium 4 processors, and hyper-threading in its B-stepping version.

The 650's SiS961 South Bridge provides USB 1.1, ATA-100 (133 in its 961B version), AC'97 six-channel audio, and integrated Ethernet/HomePNA networking. The 651 also uses the newer SiS962 South Bridge, which provides ATA133 and USB 2.0 support.

SiS645/645DX

The 645 family of SiS chipsets does not include the integrated graphics of the 650/651 family, but they are otherwise similar. They support SDRAM and DDR SDRAM, AGP 4x, and the high-speed MuTIOL North Bridge/South Bridge interface. The 645DX supports DDR333 memory, the 533MHz system bus, and the HT technologies found in the most recent Pentium 4 processors.

Both the 645 and 645DX use the SiS961 South Bridge.

SiS648/648FX/655/655FX/655TX

The SiS648 chipset is a development of the 645DX chipset, with the following differences:

• Supports DDR memory only (up to DDR333)

• 8X AGP slot

• SiS963 South Bridge (USB 2.0, IEEE 1394a support)

The SiS655 chipset is essentially a dual-channel version of the 648, supporting up to 4GB of memory with DDR266/333 memory only.

The SiS648FX chipset is a development of the 648 that supports 800MHz bus speeds of the Pentium 4.

The SiS655FX is a development of the original SiS655 chipset with the following differences:

• Supports dual-channel DDR400 memory

• Supports 800MHz bus speeds of the Pentium 4

• Supports SiS's HyperStreaming Technology, SiS's marketing term for its method of reducing data latency through improved pipelining and splitting transactions

• Has SiS964 South Bridge (eight USB 2.0 ports, eight-channel audio, SATA, RAID)

The SiS655TX is based on the SiS655FX but uses second-generation Advanced HyperStreaming Technology.

SiS R658/R659

The SiS R658 is the first SiS chipset ever to support Rambus RDRAM. Other features include

• Support for Pentium 4 processors with 533MHz and HT (B-stepping only) features

• Dual-channel support for PC1066/PC800 RDRAM (requires identical pairs of memory)

• 4GB maximum memory size

• AGP 8x interface

• MuTIOL 1G (533MHz clock speed providing more than 1GBps throughput) interface to the SiS963 South Bridge

Essentially, the R658 is an RDRAM version of the 655 chipset, and, like the 655, it uses the SiS963 South Bridge.

The R659 is based on the R658 with the following differences:

• Support for 800MHz bus speeds of the Pentium 4

• SiS HyperStreaming Technology

• Quad-channel PC1200 RDRAM

• SiS964 South Bridge

SiS661GX/SiS661FX

The SiS661GX is an integrated chipset with the following features:

• Support for Pentium 4 processors up to 533MHz processor bus with HT Technology

• Up to 2GB of DDR400 (two DIMMs) or up to 3GB of DDR333/266 (three DIMMs)

• AGP 8x video

• Integrated SiS Mirage Graphics (software-compatible with DirectX9) with CRT, TV, and LCD support; hardware acceleration for DVD playback; and shared memory of 32MB or 64MB

• SiS964/964L South Bridge

The SiS661FX is an integrated chipset that is similar to the SiS661GX, but it supports Pentium D dual-core processors and Pentium 4 HT Technology processors up to 800MHz processor bus.

SiS656/SiS656 FX

The SiS656 is the first SiS chipset to support PCI-Express and DDR2 memory. Thus, it is roughly similar to the Intel 915 series of Pentium 4 chipsets (shown earlier). Other features include

• Support for Pentium 4 processors up to 800MHz FSB, including Prescott as well as the dual-core Pentium D

• Dual-channel DDR400/333 or dual-channel DDR2 533/400MHz memory

• Maximum memory size of 4GB

• ECC memory support

• PCI-Express x16

• SiS965/965L or 966/966L South Bridge

The SiS656FX is based on the SiS656 but offers a faster maximum FSB speed of 1066MHz.

SiS649/SiS649FX

The SiS649 is a single-channel version of the SiS656. Its major features include

• Support for Pentium 4 processors up to 800MHz FSB, including Prescott and the dual-core Pentium D

• Dual-channel DDR400/333/266 or dual-channel DDR2 533/400MHz memory

• Maximum memory size of 2GB

• PCI-Express x16

• SiS965/965L or 966/966L South Bridge

The SiS649FX is based on the SiS649 but offers a faster maximum FSB speed of 1066MHz and supports DDR2 667 or DDR 400 memory.

ULi Electronics Chipsets for Pentium 4

ULi Electronics (formerly known as ALi Corporation and Acer Laboratories) has produced several chipsets for the Pentium 4 and Celeron 4 processors. Tables 4.36 and 4.37 provide an overview of these chipsets, which are discussed in the following sections.

Table 4.36. ALi Chipsets for Pentium 4

Chipset	ALADDiN-P4	M1681	M1683	M1685
North Bridge chip	M1671	M1681	M1563	M1563
Bus speed	400MHz	533/400MHz	800/533/400MHz	800/533/400MHz
Supports HT Technology	No	Yes	Yes	Yes
SMP (dual CPUs)	No	No	No	No
Memory types	PC100/133 DDR200/266/333	PC100/133 DDR200/266/333/400	PC133 DDR266/333/400	DDR266/333/400 DDR2 400/533/667
Parity/ECC	Neither	Neither	Neither	Neither
Maximum memory	3GB	3GB	4GB	3.5GB
PCI support	2.2	2.3	2.3	2.3
PCI speed/width	33MHz, 32-bit	33MHz, 32-bit	33MHz, 32-bit	33MHz, 32-bit
Video slot	AGP 4x	AGP 8x	AGP 8x	PCI-Express x16
Integrated video	No	No	No	No
South Bridge	M1535 series	M1535 series	M1535 series	M1575 series
HyperTransport NB/SB Link	N/A	400MBps	400MBps	800MBps
*Also supports hyper-threaded processors

Table 4.37 provides an overview of the ALi South Bridge chips used in ALi Corporation's chipsets for the Pentium 4; some of these South Bridge chips also support the Athlon XP and Athlon 64 processors from AMD.

Table 4.37. ALi South Bridge Chips for Pentium 4, Athlon XP, and Athlon 64

South Bridge Chip	USB Support	Number of USB Ports	ATA Support	SATA	SATA RAID	Audio	Soft Modem	10/100 Ethernet	Super I/O	PCI-Express
M1535D	1.1	4	33/66			Stereo AC'97	Yes	No	Yes	No
M1535D+	1.1	6	33/66/100/133			6-channel AC'97	Yes	No	Yes	No
M1563[*]	2.0	6	66/100/133			6-channel AC'97; SPDIF	Yes	Yes	Yes	No
M1567[^]	2.0	8	66/100/133	150MBps		7.1-channel HDA	Yes	Yes	Yes	Yes
M1573[^]	2.0	8	66/100/133	150MBps		7.1-channel HDA	Yes	Yes	Yes	Yes
M1575[^]	2.0	8	66/100/133	300MBps	0, 1, 0+1, 5, JBOD	7.1-channel HDA	Yes	Yes	Yes	Yes

^[*] Also incorporates SD and Memory Stick flash memory interfaces and supports AMD Athlon 64/Opteron/Mobile Athlon 64 processors.

^{[^]} Supports Pentium 4 and AMD Athlon 64 processors and third-party North Bridge chips such as the ATI Radeon Xpress 200.

Aladdin P4 (M1671)

The ALi Aladdin P4 was ALi's first Pentium 4-compatible chipset. Because it uses the same M1535-series South Bridge chips used by its earlier Pentium and Pentium II/III chipsets, the P4 is a traditional North Bridge/South Bridge solution. Thus, it relies on the slow (133MBps) PCI interface to carry data between the bridge chips.

The P4's major features include the following:

• 400MHz system bus

• Support for PC100/133 and DDR200/266/333 memory

• ATA-133 support (when used with the M1535D+ South Bridge)

• AGP 4x interface

• USB 1.1 ports

• ACPI power management

The P4 is also available in a version for notebook computers: the ALADDiN-P4M, which uses the D1535+ South Bridge.

M1681/M1683

ALi's M1681 chipset for the Pentium 4 processor is the first ALi chipset to use the HyperTransport high-speed direct connection between North and South Bridge chips instead of relying on the PCI bus, as with previous designs.

Its major features include

• Support for hyper-threading and 533MHz system bus

• Support for DDR memory up to DDR400 and PC100/133 SDRAM

• ATA-133

• USB 2.0

• AGP 8x interface

• Memory Stick and SD (Secure Digital) flash memory device interfaces

• ACPI power management

• HyperTransport high-speed link between North and South Bridge chips, running at >400MBps bandwidth in each direction (800MBps total throughput)

• M1563 South Bridge chip

The M1683 chipset is based on the M1681 but supports the 800MHz system bus.

M1685

Although the M1685 chipset is numbered in series with ALi's earlier Pentium 4 chipsets, it represents a major departure from the M1681/M1683 generation. The M1685 is ALi's first chipset for the Pentium 4 to adopt PCI-Express and DDR2 memory. Its major features include

• Support for the 800MHz system bus

• Support for HT Technology processors

• DDR266/333/400 or DDR-II memory

• PCI-Express x16 video slot

• 3.5GB maximum memory size

• M1563, M1567, or M1575 South Bridge chip

Although the M1685 North Bridge supports the same DDR2 memory and PCI-Express x16 technologies used by the latest Intel and SiS chipsets, the companion M1653 South Bridge lacks significant I/O support features, such as Serial ATA and ATA RAID. Thus, a motherboard using the M1685/M1563 chipset combination will not support the latest hard disks unless a discrete SATA host adapter chip is used. Some motherboards using the M1685 might use the newer M1567 (SATA RAID) or M1575 (SATA RAID 300MBps) South Bridge chips, either of which would be more satisfactory than the M1563.

ATI Chipsets for Pentium 4

ATI's original line of chipsets for the Pentium 4 integrate Radeon VE-level 3D graphics, DVD playback, and dual-display features with high-performance North Bridge and South Bridge designs. ATI uses its high-speed A-Link bus to connect its North and South Bridge chips.

The Radeon IGP North Bridge chips for Pentium 4 include the ATI A4 family, comprised of

• Radeon IGP 330

• Radeon IGP 340

The Radeon 9x00 IGP family is ATI's second generation of chipsets for the Pentium 4. The 9x00 IGP North Bridge chips feature Radeon 9200-level graphics with DirectX 8.1 hardware support and support for multiple monitors. On the other hand, the companion IXP 300 South Bridge supports Serial ATA and USB 2.0 as well as six-channel audio. The Radeon 9x00 IGP family includes

• Radeon 9100 IGP

• Radeon 9100 Pro IGP

• Radeon 9000 Pro IGP

ATI's current line of Pentium 4compatible chipsets includes the RC410 (integrates Radeon X300 3D graphics) and the RS400 (integrates Radeon X300 3D graphics and includes support for PCI-Express x16 video). Both are sold under the Radeon Xpress 200 brand name. Although ATI has made South Bridge chips in the past, its current Radeon Xpress 200 North Bridge chips can be paired with either ATI's own IXP 450 or ULi's M157x South Bridge chips.

ATI's South Bridge chips include

• IXP 150

• IXP 200

• IXP 250

• IXP 300

• IXP 400

• IXP 450

Table 4.38 summarizes the major features of the North Bridge chips, and Table 4.39 summarizes the major features of the South Bridge chips used in ATI's integrated chipsets for the Pentium 4. The Radeon IGP 330 and 340 chipsets were not widely used in desktop computers and have now been discontinued.

Table 4.38. Radeon IGP (North Bridge) Chips for Pentium 4

North Bridge Chip	Radeon IGP 330	Radeon IGP 340	Radeon 9100/PRO[2] IGP	Radeon 9000 PRO IGP	Radeon Xpress 200 (RS 400)	Radeon Xpress 200 (RC 410)
Bus speed	400MHz	400/533MHz	400/533/800MHz	400/533/800MHz	400/533/800MHz	400/533/800MHz
Hyper-Threading support	No	No	Yes	Yes	Yes	Yes
Memory types	DDR200/266	DDR200/266/333	DDR333/400 dual-channel	DDR333/400	DDR333/400; DDR2 400/533/667	DDR333/400; DDR2 400/533/667
Parity/ECC	Neither	Neither	Neither	Neither	Neither	Neither
Maximum memory	1GB	1GB	4GB	4GB	4GB	4GB
PCI support	2.2	2.2	2.3	2.3	2.3	2.3
PCI speed/width	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit	33MHz/32-bit
AGP support	4x	4x	8x	8x	No	No
PCI-Express x16	No	No	No	No	Yes	No
Integrated video	Radeon VE[1]	Radeon VE[1]	Radeon 9200[3],[4]	Radeon 9200[3],[4]	Radeon X300	RadeonX300
NS/SB interconnect speed	266MBps	266MBps	266MBps	266MBps	800MBps	800MBps
NS/SB interconnect type	A-Link	A-Link	A-Link	A-Link	HyperTransport	HyperTransport

^[2] The PRO version features improved AGP 8x performance, better memory performance, and improved DDR400 memory compatibility.

^[1] Same core as ATI Radeon 7000 with support for dual displays.

^[3] Two graphics pipelines only; discrete Radeon 9200 GPU has four.

^[4] Supports ATI SurroundView, which allows a three-monitor setup when a dual-display ATI graphics card is connected to the AGP slot. Some motherboards might not support this feature.

Table 4.39. ATI South Bridge Chips for Pentium 4

South Bridge Chip	USB Support	Number of USB Ports	ATA Support	Audio	10/100 Ethernet	High-speed Interconnect
IXP 150	2.0	6	ATA100	AC'97 2.3; 6-channel	3Com	A-Link
IXP 200/250[1]	2.0	6	ATA100	AC'97 2.3; 6-channel	3Com	A-Link
IXP 300	2.0	8	ATA133, 2 SATA	AC'97 2.3; 6-channel	3Com	A-Link
IXP 400 (SB400)	2.0	8	ATA133, 4 SATA	AC'97 2.3; 6-channel	3Com	A-Link
IXP 450	2.0	8	ATA 133, 4 SATA	AC'97 2.3; 8-channel	Realtek 8101L	HyperTransport 800MHz

^[1] IXP250 identical features to IXP200, plus it supports Wake On LAN (WOL), Desktop Management Interface (DMI), manage boot agent (MBA), and the Alert Standards Forum (ASF) mechanism.

Table 4.40. VIA Chipsets for Pentium 4 (up to 533MHz System Bus)

Chipset	P4X266	P4X266A	P4X266E	P4M266	P4X400 (P4X333)	P4X400A	P4X533
North Bridge chip	VT8753	VT8753A	VT8753E	VT8751	VT8754	VT8754CE	P4X533
Bus speed	400MHz	400MHz	400/533MHz	400MHz	400/533MHz	400/533MHz	400/533MHz
HT Technology support	No	No	No	No	No	Yes	Yes
SMP (dual CPUs)	No	No	No	No	No	No	No
Memory types	PC100/133, DDR200/266	PC100/133, DDR200/266	DDR200/266	PC100/133, DDR200/266	DDR200/266/333	DDR266/333/400	DDR200/266/333
Parity/ECC	Neither	Neither	Neither	Neither	ECC	ECC	ECC
Maximum memory	4GB	4GB	4GB	4GB	16GB	16GB	16GB
PCI support	2.2	2.2	2.2	2.2	2.2	2.2	2.2
PCI speed/width	33MHz/32-bit[*]	33MHz/32-bit[*]	33MHz/32-bit[*]	33MHz/32-bit	33MHz/32-bit[*]	33MHz/32-bit[*]	33MHz/32-bit[*]
AGP slot	4x	4x	4x	4x	8x	8x	8x
Integrated video	No	No	No	S3 Graphics ProSavage8 3D	No	No	No
South Bridge	VT8233, VT8233C, VT8233A	VT8233, VT8233C, VT8233A	VT8233, VT8233C, VT8233A, VT8235	VT8233, VT8233C, VT8233A	VT8235	VT8235	VT8237
V-Link speed	266MBps	266MBps	266MBps	266MBps	533MBps	533MBps	533MBps

^[*] Supports 66MHz/64-bit PCI when an optional VPX-64 (VT8101) chip is used.

VIA Chipsets for Pentium 4

Although VIA Technologies produces a line of chipsets for the Pentium 4, it initially lacked a license from Intel for the Socket 478 interface. This slowed acceptance of VIA's chipsets by motherboard makers until VIA and Intel reached an agreement in April 2003. Before VIA received a license to the Socket 478 interface, it used its VIA Platform Solutions Division (VPSD) to produce Pentium 4compatible motherboards for sale under a variety of brand names. With the agreement between VIA and Intel, VIA's chipsets for the Pentium 4 are now being used by most of the major third-party motherboard makers.

Tables 4.40 and 4.41 provide an overview of VIA's chipsets for the Pentium 4, including ProSavage chipsets with integrated graphics.

Table 4.41. VIA Chipsets for Pentium 4 (800MHz System Bus)

Chipset	PT800	PM800	P4M800 Pro	PT880	PT880 Ultra	PT894	PT894 Pro
North Bridge chip	PT800	PM800	P4M800 Pro	PT800	PT880 Ultra	PT894	PT894 Pro
Bus speed	400/533/800MHZ	400/533/800MHZ	400/533/800MHZ	400/533/800MHZ	1066/800/33/400MHZ	1066/800/533/400MHZ	1066/800/533/400MHZ
HT Technology support	Yes	Yes	Yes	Yes	Yes	Yes	Yes
SMP (dual-CPUs)	No	No	No	No	No	No	No
Memory	DDR266/333/400	DDR266/333/400	DDR266/333/400; DDR2 533/400	Dual-channel DDR266/33/400	Dual-channel DDR266/333/400; DDR2 533/400	Dual-channel DDR266/333/400; DDR2 533/400	Dual-channel DDR266/333/400; DDR2 533/400
Parity/ECC	ECC	ECC	ECC	ECC	ECC	ECC	ECC
Maximum memory	16GB	16GB	16GB	16GB	16GB	16GB	16GB
PCI support	2.2	2.2	2.2	2.2	2.2	2.2	2.2
PCI speed/width	33MHz/32-bit[*]	33MHz/32-bit[*]	33MHz/32-bit[*]	33MHz/32-bit[*]	33MHz/32-bit[*]	33MHz/32-bit[*]	33MHz/32-bit[*]
AGP slot	8x	8x	8x	8x	8x	No	No
PCI-Express video	No	No	No	No	x4	x16	x16, x4
Integrated video	No	S3 UniChrome Pro[#]	S3 UniChrome Pro[#]	No	No
South Bridge	VT8237	VT8237	VT8237R	VT8237	VT8237R	VT8237R	VT8237R
V-Link speed	533MBps	533MBps	1066MBps	1066MBps	1066MBps	1066MBps	1066MBps

^[*] Supports 66MHz/64-bit PCI when optional VPX-64 (VT8101) chip is used.

^[#] The UniChrome Pro features dual-monitor support, 350MHz RAMDAC, enhanced DVD playback, and DirectX 7/8/9 3D graphics support.

Table 4.42 lists the major features of the VIA South Bridge chips used in VIA's chipsets for the Pentium 4. Note that these same chips are also used by VIA chipsets for the AMD Athlon family of processors. All chipsets that use these South Bridge chips use VIA's high-speed V-Link interface between North and South Bridge chips. These chipsets connect to the VT1211 LPC (low pin count) or equivalent Super I/O chip for support of legacy devices such as serial, IR, and parallel ports and the floppy drive.

Table 4.42. VIA South Bridge Chips for Pentium 4

South Bridge Chip	USB Support	Number of USB Ports	ATA Support	SATA Support	SATA Raid Support	PCI-Express	Audio	10/100 Ethernet	Home PNA	AV-Link Through-put
VT8233	1.1	6	33/66/100	No		No	AC'97, 6-channel[1]	Yes	Yes	266MBps
VT8233A	1.1	6	33/66/100	No		No	AC'97, 6-channel[1]	Yes	No	266MBps
VT8233C	1.1	6	33/66/100	No		No	AC'97, 6-channel[1]	Yes[2]	No	266MBps
VT8235	2.0	6 33/66/100/133	No		No	AC'97, 5.1-channel[1]	Yes	No	533MBps
VT8237R[5],[6]	2.0	8	33/66/100/133	SATA-150	0,1[7]	AC'97, 5.1-channel[1],[4]	Yes	No	1066MBps
VT8251	2.0	8	33/66/100/133	SATA-300[8]	0,1,0+1, 5	X2 or x1x2	AC'97, 7.1 channel	Yes	No	1066MBs
3. 4 SATA ports with optional SATALite interface.

^[1] Integrated audio requires separate audio codec chip on motherboard; it also supports MC'97 soft modem.

^[2] 3Com 10/100 Ethernet.

^[5] Can also be used with North Bridge chips that support 533MBps interconnect speed.

^[6] Originally known as VT8237.

^[7] Supports RAID 0+1 with optional SATALite.

^[4] 8-channel (7.1) audio when optional VIA Envy 24PT PCI audio controller is used.

^[8] Supports NCQ (native command queuing).

VIA Modular Architecture Platforms (V-MAP) for Pentium 4

VIA's North and South Bridge chips for the Pentium 4 support VIA's Modular Architecture Platforms (V-MAP) designs, which enable motherboard designers to convert quickly to more advanced versions of a chipset because of a common pinout. The North Bridge chips used in all VIA Pentium 4compatible chipsets are all pin-compatible with each other, as are the 8233/8235/8237-series South Bridge chips. Thus, motherboards using these chipsets can be built in a variety of configurations. All these chipsets also support VIA's V-Link high-speed connection between the North and South Bridge chips.

VIA Apollo P4X266 Family

The VIA Apollo P4X266 is its first chipset for the Pentium 4 and Celeron 4 processors, supporting AGP 4x, 4GB of RAM, and the 400MHz system bus used by early Pentium 4/Celeron 4 processors. The P4X266A improves the memory interface and queues more instructions (up to 12) in the processor bus interface to reduce latency and improve performance. The P4X266E adds support for the 533MHz bus used in the 2.53GHz (and faster) Pentium 4 processors. It also supports both the VT8233 and newer VT8235 series of South Bridge chips.

ProSavage P4M266

The VIA ProSavage P4M266 integrates the S3 Graphics ProSavage8 2D/3D graphics accelerators with the features of the P4X266 chipset. Unlike some other chipsets with integrated graphics, the P4M266 retains an AGP 4x slot, so users can upgrade to faster AGP 4x graphics in the future.

The ProSavage8 core uses 32MB of system RAM for its frame buffer, supports AGP 8x bandwidth internally with 128-bit data paths, and features DVD DXVA Motion Compensation to improve the quality of DVD playback. In addition, it supports all members of the 8233 family of South Bridge chips.

Apollo P4X400, P4X400A, and P4X533

The VIA Apollo P4X400 chipset is an improved version of the short-lived P4X333. It's suitable for both server and workstation/desktop computer use, thanks to its support for up to 32GB of RAM and ECC memory. It also supports 400MHz and 533MHz system bus speeds and DDR memory up to 400MHz. It uses the VT8235 South Bridge, so it also supports the latest I/O standards (USB 2.0 and ATA-133).

The P4X400A chipset features improved timings and support for DDR400 memory, supports HT Technology processors, and uses the VT8235 South Bridge.

The P4X533 chipset is similar to the P4X400A but uses the VT8237 as its South Bridge chip, providing support for SATA and RAID as well as eight USB 2.0 ports and optional 7.1 audio.

All three processors use the 8x V-Link connection (533MBps) between North and South Bridge chips.

PT800/PM800/PT880/PM880

The PT8xx-series chipsets are the first VIA Technologies chipsets to support the 800MHz processor bus versions of the Pentium 4. They use the VT8237R South Bridge chips (eight USB 2.0 ports, SATA, RAID, and optional 7.1 audio) or the new VT8251 (SATA 300 with NCQ, RAID 5, and integrated 7.1 audio).

The major differences between these chipsets include

• PT800 uses single-channel DDR 400 memory and AGP 8x video, with 8x V-Link (533MBps).

• PM800 adds S3 UniChrome Pro integrated graphics to the PT800 feature set.

• PT880 is a dual-channel version of the PT800 and uses Ultra V-Link (1066MBps).

• PM880 adds S3 UniChrome Pro integrated graphics to the PT880 feature set.

PT880 Ultra/PT894/PT894 Pro

The VIA PT880 Ultra, PT894, and PT894 Pro are based on the PT880 chipset, with the following differences:

• These chipsets support DDR2 memory up to 533MHz, while continuing to support DDR memory.

• The PT880 Ultra supports AGP 8x as well as PCI-Express x4 graphics.

• The PT894 and PT894 Pro support PCI-Express x16 instead of AGP 8x graphics; PT894 Pro also adds support for PCI-Express x4 graphics.

• The PT894 and PT894 Pro support the 1066MHz front side bus.

They use the VT8237R South Bridge chips (eight USB 2.0 ports, SATA, RAID, and optional 7.1 audio) or the new VT8251 (SATA 300 with NCQ, RAID 5, and integrated 7.1 audio).

Figure 4.41 illustrates the PT894 Pro's block diagram.

Figure 4.41. VIA's PT894 Pro chipset for the Pentium 4 combines dual-channel DDR/DDR2 memory support with dual PCI-Express video slots and the new VT8251 South Bridge.