Section 1.2. Designing the Perfect PC


1.2. Designing the Perfect PC

A sign you'll see in many repair shops says, "Good. Cheap. Fast. Pick any two." That's also true of designing a PC. Every choice you make involves a trade-off, and balancing those trade-offs is the key to designing a PC that's perfect for your needs. Each of the project system chapters has a graphic that looks something like what's shown to the right.

Ah, if it were only true. Reality, of course, is different. One can't put the highest priority on everything. Something has to give. As Frederick the Great said of designing military defenses, "He who defends everything defends nothing." The same is true of designing a PC.

DESIGN PRIORITIES

Price

Reliability

Size

Noise level

Expandability

Processor performance

Video performance

Disk capacity/performance



If you focus on these elements while designing your PC, you'll soon realize that compromises are inevitable. If small size is essential, for example, you must make compromises in expandability, and you may very well have to compromise in other respects. The trick is to decide, before you start buying components, which elements are essential, which are important, which would be nice to have, and which can be ignored.

A Dissenting View

Our technical reviewer Jim Cooley says, "I disagree. You don't load the crap on your machines that Average Joe does, but if you did you'd find most crashes were software related, not hardware."

Jim is right. Years ago, before we migrated to Linux, we were very careful to avoid Windows Rot, going as far as to reinstall Windows from scratch every few months. A fresh Windows install with current drivers is reasonably stable (although not remotely in the same class as Linux), but as you use a Windows system over weeks and months, its stability degrades gradually (or not so gradually).


Once you have the priority of those elements firmly fixed in your mind, you can make rational resource allocations and good purchasing decisions. It's worth looking at each of these elements in a bit more detail.


Price

We put price first, because it's the 900-pound gorilla in system design. If low price is essential, you'll be forced to make compromises in most or all of the other elements. Simply put, high performance, reliability, low noise, small size, and other desirable characteristics cost money. We suggest you begin by establishing a ballpark price range for your new system and then play "what-if" with the other elements. If you've set too low a price, it will soon become clear that you'll need to spend more. On the other hand, you may well find that you can get away with spending less and still get everything you want in a system.


Reliability

We consider high reliability essential in any system, even the least expensive entry-level PC. If a system is unreliable, it doesn't matter how feature-laden it is, or how fast, or how cheap. We always aim for 5-star reliability in systems we design for ourselves and others, although sometimes price and other constraints force us to settle for 4-star reliability. The best mass-market systems may have 3-star reliability, but most deserve only a 1- or 2-star rating.

What does reliability mean, and how do you design for it? A reliable system doesn't crash or corrupt data. It runs for years with only an occasional cleaning. We are always amused when people claim Windows is crash-prone. That is true of Windows 9X, of course, but Windows NT/2000/XP has never blue-screened on us except when there was a hardware problem, and that's going back to the early days of Windows NT 4. We're not Microsoft fanboysfar from itbut the truth is that the vast majority of system crashes that are blamed on Windows are actually caused by marginal or failing hardware.

There are a few simple rules for designing a reliable system. First, use only top-quality parts. They don't have to be the fastest availablein fact high-performance parts often run hotter and are therefore less reliable than midrange onesbut top-quality components may be a full order of magnitude more reliable than run-of-the-mill ones. Use a motherboard built around a reliable chipset and made by a top-notch manufacturer. For Intel processors, Intel motherboards and chipsets are the standard by which we judge, and for AMD processors the same is true of ASUS motherboards and nVIDIA chipsets. Use a first-rate power supply and the best memory available. Avoid cheap cables. Keep the system cool and clean out the dust periodically. That's all there is to it. Following this advice means the system will cost a bit more, but it will also be significantly more reliable.

Determining Quality

Of course, this raises the question, how does one tell great from good from bad? Discriminating among companies and brands is difficult for someone who doesn't know which companies have an established reputation for quality and reliability, which purvey mostly junk, and which are too new to have a track record. All of the components and brands we recommend in this book are safe choices, but the proliferation of brands makes it easy to choose inferior components.

If you must use components other than those we recommend, the best way to avoid inferior components is to do your homework. Visit the manufacturers' web sites. A good web site doesn't guarantee that the products are also good, but a poor web site almost certainly means the products are also poor. Check online reviews of products you are considering, and visit discussion forums for those components. In the end, trust your own judgment. If a component appears cheap, it probably isn't reliable. If the documentation is sparse or isn't written in good English, that tells you something about the likely quality of the component as well. If the component has a much shorter warranty than similar components from other manufacturers, there's probably good reason.

Finally, although price is not invariably a perfect predictor of component quality, it's usually a very good indicator. The PC component business is extremely competitive, so if a product sells for much less than similar competing products, it's almost certain that that product is inferior.



Size

Most people prefer a small PC to a large one, but it's easy to design a system that's too small. Albert Einstein said, "Everything should be made as simple as possible, but not simpler." In other words, don't oversimplify. Use the same rule when you choose a size for your PC. Don't over-smallify.

Choosing a small case inevitably forces you to make compromises. A small case limits your choice of components, because some components simply won't fit. For example, you may have to use a different optical drive than you'd prefer because your first choice is too long to fit into the case. A small case also limits the number of components you can install. For example, you may have to choose between installing a card reader and installing a second hard drive. Because a small case can accept fewer (and smaller) fans, it's more difficult to cool the system properly. To move the same amount of air, a smaller fan must spin faster than a larger fan, which generates more noise. The limited case volume makes it much harder to work inside the case, and makes it more difficult to route cables to avoid impeding air flow. All other things being equal, a small PC will cost more, run slower, produce more heat and noise, or be less reliable than a standard-size PC, or all of those.

For most purposes, the best choice is a standard mini- or mid-tower case. A full-tower case is an excellent choice for a server, or for an office system that sits on the floor next to your desk. Choose a microATX or other small form factor case only if size is a high priority.


Noise level

Noise level has become a major issue for many people. If you think PCs are getting louder, it's not your imagination. As PCs get faster and faster, they consume more power and produce more heat. The most convenient way to remove heat is to move a lot of air through the case, which requires fans. Fans produce noise.

Just a few years ago, most PCs had only a power supply fan. A typical modern PC may have half a dozen or more fansthe power supply fan, the CPU fan, a couple of supplemental case fans, and perhaps fans for the chipset, video card, and hard drive. All of these fans are needed to keep the components cool, but all of them produce noise. Fortunately, there are methods to cool a PC properly while minimizing noise. We'll look at some of those methods later in this section.


Expandability

Expandability is worth considering when you design a PC. For some systems, expandability is unimportant. You design the system for a particular job, install the components you need to do that job, and never open the case again except for routine cleaning and maintenance. For most general-purpose systems, though, expandability is desirable. For example, if you need more disk space, you might prefer to add a second hard drive rather than replace the original drive. You can't do that unless there's a vacant drive bay. Similarly, integrated video might suffice originally, but you may later decide that you need faster video. If the motherboard you used has no AGP or PCI Express (PCIe) video slot, you're out of luck. The only option is to replace the motherboard.

Keep expandability in mind when you choose components, so you won't paint yourself into any corners. Unless size constraints forbid it, choose a case that leaves plenty of room for growth. Choose a power supply that has sufficient reserve to support additional drives, memory, and perhaps a faster processor. Choose a motherboard that provides sufficient expansion slots and memory sockets to allow for possible future expansion. Choose less flexible components only if you are certain that you will never need to expand the system.


Processor performance

Most people worry too much about processor performance. Here's the truth. Midrange processorsthose that sell for $150 to $225are noticeably faster than $50 to $100 entry-level processors. The most expensive processors, which sell for up to $1,000, are noticeably faster than midrange processors. Not night-and-day different, but noticeable. For casual usebrowsing the Web, checking email, word processing, and so onchoose a $75 "value" processor from AMD or Intel. For a general-purpose system, choose a Pentium D, Core 2, or Athlon 64 processor that sells for $150 to $225 in retail-boxed form. It makes little sense to choose a high-end processor unless cost is no object and performance is critical.


Video performance

Video performance, like processor performance, usually gets more attention than it deserves. It's probably no coincidence that processors and video adapters are two of the most heavily promoted PC components. When you design your PC, be careful not to get caught up in the hype. If the PC will be used for intense 3D gaming or similarly demanding video tasks, you need a high-end video adapter (or dual video adapters). Otherwise, you don't.

Integrated videoa video adapter built into the motherboardis the least expensive video solution, and is perfectly adequate for most uses. The incremental cost of integrated video ranges from $0 to perhaps $10, relative to a similar motherboard without integrated video. The next step up in video performance is a standalone video adapter, which requires that the motherboard have a slot to accept it. Standalone video adapters range in price from $25 or so up to $500 or more. The old 80/20 rule applies to video adapters, which is to say that a $100 video adapter provides most of the performance and features of a $500 adapter.

More expensive video adapters provide incrementally faster 3D video performance and may support more recent versions of Microsoft DirectX, both of which are of interest to serious gamers. Expensive video adapters also run hot and are generally equipped with dedicated cooling fans, which produce additional noise.

When you design your PC, we recommend using integrated video unless you need the faster 3D performance a standalone video adapter can provide. If you choose integrated video, make sure the motherboard has an AGP or PCIe slot available in case you later decide to upgrade the video.


Disk capacity/performance

A mainstream 7,200 RPM ATA or Serial ATA hard drive is the best choice for nearly any system. Such drives are fast, cheap, and reliable. The best models are also relatively quiet and produce little heat. When you design your system, use one of these drives (or two, mirrored for data protection) unless you have good reason to do otherwise. Choose a 10,000 RPM ATA drive if you need the highest possible disk performanceas for a server or personal workstationand are willing to pay the price. Avoid 5,400 RPM ATA drives, which cost only a few bucks less than 7,200 RPM models, but have noticeably poorer performance.

AGP Versus PCIe

AGP is an older video adapter interface that is gradually being replaced by the newer PCIe interface. Many AGP motherboards and video adapters are still availableand are likely to remain so for quite some timebut AGP is a dying standard. For example, when we searched the NewEgg site in November 2006, we found 150 AGP video adapter models available, versus 356 PCIe models. When we did that search a few months earlier, there were about 200 AGP models, versus about 300 PCIe models.

AGP video adapters and motherboards, with few exceptions, are restricted to older technology. The latest and fastest video and motherboard chipsets and support for the fastest memory are available only in PCIe models. Although it may seem a bad idea to buy into an obsolescent technology like AGP, an AGP-based motherboard is often a good and economical choice, particularly for a system you are building on a tight budget.


See Chapter 2 for specific component recommendations.

1.2.1. Balanced Design

Novice PC builders often ignore the important concept of balanced design. Balanced design means allocating your component budget to avoid bottlenecks. If you're designing a gaming PC, for example, it makes no sense to spend $50 on the processor and $500 on the video card. The resulting system is nonoptimal because the slow processor is a bottleneck that prevents the expensive video adapter from performing to its full potential.

The main enemy of balanced design is the constant hype of manufacturer advertising and enthusiast web sites (which sometimes amount to the same thing). It's easy to fixate on the latest "must-have" component, even though its price may be much too high to justify. Many people just can't help themselves. Despite their best intentions, they end up spending $700 for a premium LCD display when a $400 model would have done just as well, or they buy a $400 video adapter when a $150 adapter would suffice. If your budget is unlimited, fine. Go for the latest and best. But if you're building a system to a fixed budget, every dollar you spend needlessly on one component is a dollar less you have to spend somewhere else, where it might make more difference.

Balanced design does not necessarily mean giving equal priority to all system components. For example, we have built servers in which the disk arrays and tape backup drive cost more than $10,000 and the rest of the system components totaled less than $2,000. A balanced design is one that takes into account the tasks the system must perform and allocates resources to optimize performance for those tasks.

But balanced design takes into consideration more than simple performance. A truly balanced design accommodates nonperformance issues such as physical size, noise level, reliability, and efficient cooling. You might, for example, have to choose a less expensive processor or a smaller hard drive in order to reserve sufficient funds for a quieter case or a more reliable power supply.

The key to achieving a balanced design is to determine your requirements, look dispassionately at the available alternatives, and choose accordingly. That can be tougher than it sounds.

1.2.2. Designing a Quiet PC

The ongoing PC performance race has had the unfortunate side effect of making PCs noisier. Faster processors use more power, which in turn requires larger (and noisier) power supplies. Faster processors also produce more heat, which requires larger (and noisier) CPU coolers. Modern hard drives spin faster than older models, producing still more noise and heat. Fast video adapters have their own cooling fans, which add to the din. The days when a high-performance PC sat under your desk making an unobtrusive hum are long gone.

Fortunately, there are steps you can take to reduce the amount of noise your PC produces. No PC with moving parts is completely silent, but significant noise reductions are possible. Depending on your requirements and budget, you can build a PC that is anything from quietly unobtrusive to nearly silent. The key to building a noise-reduced PC is to recognize the sources of noise and to minimize or eliminate noise at the source.

The major sources of noise are typically the power supply, CPU cooler fan, and supplementary case fans. Minor sources of noise include the hard drive, chipset fan, video adapter fan, and optical drive. As you design your PC, focus first on major noise sources that can be minimized inexpensively, then minor noise sources that are cheap to deal with, then major noise sources that are more expensive or difficult to minimize, and finally (if necessary) minor noise sources that are expensive or difficult to fix. Use the following guidelines:


Choose a low-power processor

The amount of power consumed by the processor has a direct effect on the noise level of the system. The peak power consumption of mainstream processors ranges from less than 70W to more than 130W. That power ends up as waste heat that must be exhausted from the case. Using a lower-power processor produces less waste heat, which in turn allows you to use a quieter CPU cooler, fewer and quieter case fans, and so on.

Power consumption isn't necessarily proportional to processor performance. For example, an AMD Athlon 64 X2 that draws 70W peak power may be faster than an Intel Pentium D that draws 130W, and an Intel Core 2 Duo processor that draws only 60W may be faster than either, at least for some tasks. None of this is to say that there's anything wrong with choosing a high-wattage processor, but doing so complicates cooling and noise issues.


Choose a quiet case

Inexpensive cases are designed with little thought to noise abatement. Better cases incorporate numerous design features that reduce noise, including large, slow-spinning exhaust fans, sound-absorbing composite panels, rubber shock mounts for drives that isolate vibration, and so on. We cover case considerations thoroughly in the next chapter.


Choose a quiet power supply

In most systems, the power supply is potentially the first or second largest noise source, so minimizing power supply noise is critical.

  • At the first level, choose a noise-reduced power supply, such as the Antec TruePower (http://www.antec.com) or PC Power & Cooling Silencer (http://www.pcpowercooling.com) models we recommend in the next chapter. Such power supplies cost little or no more than competing models of equivalent capacity and quality, and are noticeably quieter. A system that uses one of these power supplies can be quiet enough to be unobtrusive in a normal residential environment.

  • The next step down in noise level is a power supply that is specifically designed to minimize noise, such as the Antec NeoHE series, Enermax NoiseTaker series (http://www.enermaxusa.com), or Seasonic S12 series (http://www.seasonicusa.com). These power supplies cost a bit more than comparable noise-reduced power supplies, but produce as little as 18 dB at idle, and not much more under load. A system that uses one of these power supplies (and other similarly quiet components) can be nearly inaudible in a normal residential environment.

  • Finally, there are power supplies that substitute huge passive heatsinks for cooling fans. These power supplies, such as the Antec Phantom 350 and the Silverstone ST30NF (http://www.silverstonetek.com), have no moving parts, and the only noise they produce is a slight buzz from the electronic components. (The Antec Phantom 500 includes an "emergency" fan that runs only if the power supply begins to overheat. Up to 200W or so, the fan doesn't run and the power supply is completely silent; above 200W, the fan kicks in, and this power supply becomes a bit louder than the best quiet fan-based power supplies.)

Monitoring CPU Temperature

Most modern motherboards provide temperature sensors at important points such as the CPU socket. The motherboard reports the temperatures reported by these sensors to the BIOS. You can view these temperatures by running BIOS Setup and choosing the option for temperature reporting, which can usually be found under Advanced Hardware Monitoring, or a similar menu option. Alternatively, most motherboards include a monitoring utilityIntel's, for example, is called the Intel Active Monitorthat allows you to monitor temperatures from Windows rather than having to run BIOS Setup.

CPU temperature can vary dramatically with changes in load. For example, a CPU that idles at 30°C may reach 50°C or higher when it is running at 100% capacity. A hot-running modern processor such as a fast Pentium D may reach temperatures of 70°C or higher under load, which is perilously close to the maximum acceptable temperature for that processor. It is therefore very important to verify that your CPU cooler and system fans are doing their jobs properly.

An idle temperature of 30°C or lower is ideal, but that is not achievable with the hottest processors, which idle at 40°C or higher with any but the most efficient CPU coolers. In general, a CPU cooler that produces an idle temperature of 40°C or lower suffices to cool the CPU properly under load.

If you want to verify temperature under load, run an application that loads the CPU with intense calculations, ideally with lots of floating-point operations. Two such applications we have used are the SETI@home client (http://setiathome.ssl.berkeley.edu) and the Mersenne Prime client (http://mersenne.org). Run the application for an hour to ensure that the CPU has reached a steady-state temperature, and then use the temperature monitoring application to view the temperature while the application is still running.



Choose an efficient power supply

Power supply efficiency has a direct bearing on system noise level. Every power supply requires higher input power than the output power it provides, and that power difference is converted to heat within the power supply. For example, if the system actually requires 200W from the power supply, a 67% efficient power supply draws 300W of input power to provide that 200W of output power (200W/0.67 = 300W). That extra 100W is converted to heat within the power supply. An 85% efficient power supply requires only about 235W of input power to provide 200W of output power. The difference between 300W input and 235W input power translates to an extra 65W of heat within your system. The efficiency of mainstream power supply models ranges from about 65% to about 85%.


Choose a quiet CPU cooler

As processor speeds have increased over the last few years, manufacturers have gone from using passive heatsinks to using heatsinks with slow, quiet fans to using heatsinks with fast, loud fans. Current processors differ greatly in power consumption from model to model. At the lower end of the rangeless than 50Wnearly any decent CPU cooler can do the job with minimal noise, including the stock CPU coolers bundled with retail-boxed processors and inexpensive third-party units. At the middle of the range50W to 90Wstandard CPU coolers begin to produce intrusive noise levels, although specialty quiet CPU coolers can cool a midrange processor with little or no noise. At the upper end of the range, even the quietest fan-based CPU coolers produce some noise.

  • For a processor with low to moderate power consumption, try using the stock CPU cooler supplied with the retail-boxed processor. If it produces too much noise, install an in-line resistor to reduce the voltage supplied to the fan, which reduces fan speed and noise. Resistor kits (sometimes called voltage or fan speed controllers) are sold by quiet-PC vendors such as FrozenCPU (http://www.frozencpu.com), QuietPC USA (http://www.quietpcusa.com), and Endpcnoise.com (http://www.endpcnoise.com).

  • For processors with high power consumption, there are several alternatives. Some of the CPU coolers bundled with Intel Pentium D processors are reasonably quiet in stock form, and can be quieted further while still providing adequate cooling by using an in-line resistor to drop the supply voltage to 7V. However, Intel uses different CPU cooler models and changes them without notice, so which you get is hit or miss. For the quietest possible fan-based cooler, you can install a premium CPU cooler from manufacturers such as Thermalright (http://www.thermalright.com) and Zalman (http://www.zalmanusa.com).

  • To minimize noise for any processor, install a Thermalright or Zalman unit. For processors with low to midrange power consumption, some of these premium coolers can be run in silent (fanless) mode, which completely eliminates CPU cooler noise.


Choose quiet case fans

Most modern systems have at least one supplemental case fan, and some have several. The more loaded the system, the more supplemental cooling you'll need to use. Use the following guidelines when selecting case fans:

  • Case fans are available in various sizes from 60mm to 120mm or larger. All other things being equal, a larger fan can move the same amount of air with less noise than a smaller fan, because the larger fan doesn't need to spin as fast. Of course, the fan mounting positions in most cases are of fixed size, so you may have little choice about which size fan(s) to use. If you do have a choicefor example, if the case has two or three fan positions of different sizeuse the largest fan that fits.

  • Case fans vary significantly in noise level, even for the same size and rotation speed. Many factors come into play, including blade design, type of bearings, grill type, and so on. In general, ball bearing fans are noisier but more durable than fans that use needle or sleeve bearings.

    CPU Coolers and Motherboard Compatibility

    If you choose an aftermarket CPU cooler, verify that it is physically compatible with your motherboard. Quiet CPU coolers often use very large heatsinks, which may conflict with protruding capacitors and other motherboard components. Most premium CPU cooler manufacturers post compatibility lists on their web sites.


  • The noise level of a fan can be reduced by running it at a lower speed, as long as it moves enough air to provide proper cooling. The simplest method to reduce fan speed is to install an in-line resistor to reduce the supply voltage to 7V. These are available from the sources listed above, or you can make your own with a resistor from RadioShack or another electronics supply store. Some fans include a control panel, which mounts in an available external drive bay and allows you to control fan speed continuously from zero to maximum by adjusting a knob. Finally, some fans are designed to be controlled by the power supply or a motherboard fan connector. These fans vary their speed automatically in response to the ambient temperature, running at high speed when the system is heavily loaded and producing lots of heat, and low speed when the system is idle.

  • The mounting method you use makes a difference. Most case fans are secured directly to the chassis with metal screws. This transfers vibration directly to the chassis panels, which act as sounding boards. A better method is to use soft plastic snap-in connectors rather than screws. These connectors isolate vibration to the fan itself. Better still is to use the soft plastic snap-in connectors in conjunction with a foam surround that insulates the fan frame from the chassis entirely.

Silent PC Review

Silent PC Review (http://www.silentpcreview.com) is an excellent source of information about quiet PC issues. The site includes numerous articles about reducing PC noise, as well as reviews of quiet PC components, a forum, and other resources.


The preceding six elements are the major steps required to quietize your PC. Once you minimize noise from those major sources, you can also take the following steps to reduce noise from minor sources. Some of these steps cost little or nothing to implement, and all contribute to quieting the PC.


Put the PC on a mat

Rather than put the PC directly on your desk or the floor, put a sound-deadening mat between it and the surface. You can buy special mats for this purpose, but we've used objects as simple as a couple of mouse pads, front and rear, to accomplish the same thing. The amount of noise reduction from this simple step can be surprisingly large.


Choose a quiet hard drive

Once you've addressed the major noise sources, hard drive noise may become noticeable, particularly during seeks. The best way to reduce hard drive noise is to choose a quiet hard drive in the first place. Seagate Barracuda ATA and SATA models are the quietest mainstream hard drives. To reduce hard drive noise further you can use a Smart Drive Enclosure or the Zalman Hard Drive Heatpipe, both of which are available from the sources listed above.


Choose a video card with a passive heatsink

All video adapter chipsets produce significant heat, but most use a passive heatsink rather than a fan-based cooler. If possible, choose a video adapter with a passive heatsink. If you must use a high-end video adapter with a fan-based cooler, consider replacing that cooler with a Zalman Video Heatpipe. The small fans used on video adapters typically run at high speeds and are quite noisy, so replacing the cooler with a passive device can reduce noise noticeably.


Choose a motherboard with a passive heatsink

The north bridge chip of modern chipsets dissipates significant heat. Most motherboards cool this chip with a large passive heatsink (see, for example, Figure 1-5), but some use a fan-based cooler. Again, these coolers typically use small, fast fans that produce significant noise. If you have a choice, pick a motherboard with a passive heatsink. If you must use a motherboard with a fan-based chipset cooler, consider replacing that cooler with a Zalman Motherboard Heatsink.

1.2.3. Designing a Small PC

At the beginning of the millennium, some forward-thinking PC builders and manufacturers began to design and build PCs smaller and/or more portable than traditional mini-tower systems. Small PCs have become extremely popular, and it's no wonder. These systems are small, light, easily portable, and fit just about anywhere. In order of decreasing size, small/portable PCs fall into four broad categories:


LAN party PC

A LAN Party PC is essentially a standard ATX mini- or mid-tower system with a handle and other modifications to increase portability, port accessibility, and other factors important in a "totable" PC. Most LAN party cases are constructed largely of aluminum to minimize weight and maximize cooling efficiency. LAN party PCs are often "tricked-out" with colorful motherboards, clear side panels, fluorescent lights, fans, and cables, and similar visual enhancements. Despite the customizations, LAN party PCs are based on industry-standard components and are as capable as any standard PC.


microATX PC

A microATX PC is basically a cut-down version of a standard ATX PC. The microATX case and motherboard are smaller and provide less expandability, but are otherwise comparable in features and functionality to a standard ATX system. The great advantage of microATX PCs relative to the smaller styles described next is that microATX PCs use industry-standard components. microATX cases are available in two styles. Slimline cases are about the size and shape of a VCR. "Cube" cases are typically 8" tall and roughly a foot wide and deep. The relatively small case capacity makes cooling more difficult and puts some restraints on the number and type of hard drives, expansion cards, and other peripherals you can install, but it is possible to build a reliable, high-performance PC in the microATX form factor.


Small Form Factor (SFF) PC

Small Form Factor (SFF) means different things to different people. We use the term to mean the cube-style form factor pioneered by Shuttle (http://us.shuttle.com) with their XPC models. In fact, Shuttle says that SFF stands for Shuttle Form Factor. Other companies, including Soltek, Biostar, and others, now produce cube-style SFF systems. These true SFF systems use proprietary cases, power supplies, I/O templates, and motherboards, which limits their flexibility. In effect, "building" an SFF system consists of buying a bare-bones system with case, power supply, and motherboard, and adding your choice of memory, drives, video adapter, and so on. SFF PCs are typically more expensive, slower, and less reliable than standard-size or microATX PCs, but they are noticeably smaller.


Mini-ITX PC

Mini-ITX is a semi-proprietary form factor pioneered by VIA Technologies. Although a few minor third-party manufacturers supply Mini-ITX components, VIA products dominate the Mini-ITX market. Mini-ITX motherboards are 170mm (6.7") square, and are in effect smaller versions of microATX motherboards. Although Mini-ITX motherboards are available that accept Socket 479 Intel Pentium M and Intel Celeron M processors, the majority of Mini-ITX systems use VIA motherboards with embedded processors.. These processors are very slow relative to modern AMD and Intel processors, and Mini-ITX motherboards are relatively expensive. Even so, Mini-ITX has its place, for systems that do not require high performance but need to be small and very quiet. Mini-ITX motherboards are so small that they can be built into enclosures as small as a cigar box (literally), and the flip side to low processor performance is that these processors consume little power and produce little heat. Most Mini-ITX systems use passive cooling and "wall-wart" power supplies, which eliminates fan noise and allows the system to be almost totally silent. Mini-ITX is most appropriate for such "appliance" applications as small Linux servers, routers, and satellite DVR playback-only systems.

Small Outside Means Small Inside

The limited space available in cube-style SFF cases restricts component choice. For example, you may have to purchase special low-profile memory modules and you may not be able to install full-length, standard-height expansion cards. The tiny case volume also makes heat dissipation critical. For example, you may not be able to use the fastest available processors because the case is not capable of cooling them sufficiently.


Table 1-1 lists the characteristics of each of these system types relative to a standard mini/mid-tower desktop system, using the rankings of Excellent (E), Very Good (VG), Good (G), Fair (F), and Poor (P).

Table 1-1. Small system strengths and weaknesses
 

Desktop

LAN party

microATX

SFF

Mini-ITX

Typical case volume (liters)

35 to 60

25 to 40

12 to 20

8 to 12

2.5 to 9

Size

P to F

F to G

G to VG

VG to E

E

Cost efficiency

E

VG

E

P to F

P to F

Reliability

E

F to VG

VG to E

F to VG

F to VG

Portability

P

VG to E

F to VG

VG to E

VG to E

Noise level

VG to E

F to VG

VG to E

P to VG

E

Cooling

E

G to E

G to VG

P to F

F to E

Upgradability/expandability

E

VG to E

F to VG

F to G

P

Processor performance

E

E

VG to E

VG to E

P

Graphics performance

E

E

VG to E

F to E

P

Disk capacity/performance

E

E

G to VG

G to VG

P


Table 1-1 presents best-case scenarios for each of the form factors. For example, not all standard desktop systems have excellent performance, nor are all of them extremely quiet.

Rather, this table presents the best that can be done within the limitations of each form factor, which may vary according to the specific components you select.

If you need to design a small PC, recognize that each step down from standard mini-tower size involves additional compromises in performance, cost, reliability, noise level, and other key criteria. Reducing case size limits the number and type of components you can install and makes it more difficult to cool the system effectively. It also makes it harder to quiet the PC. For example, small cases often use relatively loud power supplies. Because the power supply is proprietary, installing an aftermarket quiet power supply is not an option. Similarly, using a small case forces you to trade off performance against cooling against noise. For example, you may be forced to use a slower processor than you'd like, because the necessary CPU cooler for a faster processor is too large to fit in the available space or is louder than acceptable.

When it comes to designing small PCs, our rule is to use a standard mini-tower system whenever possible. If that's too large, step down to a microATX system. If a microATX system is too large, we suggest you rethink your priorities. Perhaps you could free some additional space by moving things around, or perhaps you could place the PC in a different position. Try hard to avoid using any form factor smaller than microATX.

Then, if and only if you are certain that the trade-offs are worth it, buy a bare-bones SFF system and build it out to meet your requirements. We don't think of Mini-ITX systems as direct competitors to traditional PCs at all. They're simply too slow to be taken seriously as a mainstream PC. Instead, we suggest you consider Mini-ITX systems to be special, relatively expensive, low-performance computing appliances that are suitable only for very specialized applications.




Building the Perfect PC
Building the Perfect PC, Second Edition
ISBN: 0596526865
EAN: 2147483647
Year: 2006
Pages: 84

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