Building the Perfect PC

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 tradeoff, and balancing those tradeoffs is the key to designing a PC that’s perfect for your needs. Each of the project system chapters has a graphic that represents the relative importance of different elements and looks something like what’s shown to the left.

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.

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.

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 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 that 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 fans—far from it—but the truth is that the vast majority of system crashes that are blamed on Windows are actually caused by marginal or failing hardware. (We just checked the uptime of our Windows NT 4 Server box, which has been running for 322 days without a reboot.)

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 available—in fact, high-performance parts often run hotter and are therefore less reliable than midrange ones—but 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; Intel motherboards and chipsets are the standard by which we judge. Use a first-rate power supply and the best memory available. Avoid cheap cables. Keep the system cool and be sure to 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 ones purvey mostly junk, and which ones 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 products is to do your homework. Visit the manufacturers’ web sites, check online reviews of products you are considering, and visit discussion forums for the components in question. 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 well written, 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 to be 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. It also limits the number of components you can install. For example, you may have to choose between installing a floppy drive 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 volume of the case makes it much harder to work inside it, and makes it more difficult to route cables to avoid impeding airflow. All other things being equal, a small PC will cost more, run slower, produce more heat and noise, and/or be less reliable than a standard-size PC.

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 small 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 fans—the 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, embedded video might suffice originally, but you may later decide that you need faster video. If the motherboard you used has no AGP slot, you’re out of luck. The only option is to replace the motherboard.

Keep expandability in mind when you choose components so that you don’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. Don’t choose less flexible components unless 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 processors—those that sell for $150 to $225—are 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 use—browsing the Web, checking email, word processing, and so on—a $75 AMD Athlon XP is perfectly adequate. For a general-purpose system, the best choice is a Pentium 4, Athlon XP, 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. Otherwise, you don’t.

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

More expensive AGP adapters provide incrementally faster 3D video performance and may support more recent versions of Microsoft DirectX; both of these characteristics are of interest to serious gamers. Expensive AGP adapters also run hot and are generally equipped with dedicated cooling fans, which produce additional noise. Some fast AGP adapters, particularly nVIDIA models, trade off lower 2D display quality for faster 3D performance.

When you design your PC, we recommend using embedded video unless you need the faster 3D performance provided by an AGP video adapter. If you choose embedded video, make sure the motherboard has an AGP 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 15,000 RPM SCSI drive if you need the highest possible disk performance—as for a server or personal workstation—and are willing to pay the price. Avoid 5,400 RPM ATA drives, which cost a few bucks less than 7,200 RPM models but have noticeably poorer performance.

See Chapter 2 for specific component recommendations.

Balanced design

Novice PC builders often ignore the important concept of balanced design. Balanced design means allocating your component budget to avoid bottle-necks. 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 non-optimal 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 if its price is much too high to justify. Many people just can’t help themselves. Despite their best intentions, they end up spending $250 on the latest super DVD burner when a $100 burner would have done just as well, or they buy a $300 video adapter when a $125 adapter would suffice. If your budget is unlimited, fine. Go for the latest and best. But if you’re building a system on 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 non-performance 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.

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 that noise at the source.

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

Choose a quiet power supply

In most systems, the power supply is the primary noise source, so minimizing power supply noise is critical.

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 utility—Intel’s, for example, is called the Intel Active Monitor—that 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 Prescott-core Pentium 4 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.

— At the first level, you can choose a standard power supply that is quieter than the norm, such as the Antec TruePower (http://www.antec-inc.com) or the PC Power & Cooling Silencer (http://www.pcpowercooling.com), which we describe in the next chapter. Such power supplies cost little or no more than equivalent competing models, and are considerably 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 is a power supply that is specifically designed to minimize noise, such as those made by Nexus (http://www.nexustek.nl) and Zalman (http://www.zalmanusa.com). These power supplies cost a bit more than comparable standard 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 completely silent power supplies, with no moving parts, that use huge passive heatsinks or convective water cooling to dissipate heat. We haven’t used any of those, so we can’t comment on them.

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, and finally to using heatsinks with fast, loud fans. Current processors vary in power consumption from less than 30W to more than 100W, with proportionate differences in heat production. At the lower end of that range—30W to 50W—nearly any decent CPU cooler can do the job with minimal noise, including the stock CPU coolers bundled with retail-boxed processors or inexpensive third-party units like those made by Dynatron (http://www.dynatron-corp.com). In the middle of the range—50W to 80W—standard 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 noticeable noise.

— For a slow processor, try the stock heatsink/fan unit supplied with the retail-boxed processor. If it produces too much noise, install an inline resistor to reduce the voltage supplied to the fan, which reduces fan speed and noise. Such resistor kits are available from specialty quiet-PC vendors such as QuietPC USA (http://www.quietpcusa.com) and Endpcnoise.com (http://www.endpcnoise.com).

— For a midrange or fast processor, there are several alternatives. Some of the CPU coolers bundled with Intel Pentium 4 processors are reasonably quiet in stock form, and can be quieted further while still providing adequate cooling by using an inline resistor to drop the supply voltage to 7V. However, Intel uses different CPU cooler models and changes them without notice, so what you end up getting is hit or miss. For the quietest possible fan-based cooler, use the Thermalright SLK-900U/A (http://www.thermalright.com) for an Intel Celeron/Pentium 4 or AMD Athlon, or the Zalman CNPS7000A-Cu or CNPS7000A-AlCu for an Intel Celeron/Pentium 4 or an AMD Athlon/Athlon 64.

— To minimize noise for any processor, install one of the Thermalright or Zalman units listed above. In particular, with slow and midrange processors (up to the Northwood-core Pentium 4/2.8), Zalman “flower” coolers can be run in silent (fanless) mode, which completely eliminates CPU cooler noise.

Warning

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.

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 choice—for example if the case has two or three fan positions of different sizes—use 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.

— The noise level of a fan can be reduced by running the fan at a lower speed, as long as it still moves enough air to provide proper cooling. The simplest method to reduce fan speed is to install an inline 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 Radio Shack or other 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 at 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.

What Are dBs, Anyway?

Disclaimer: The following is a gross oversimplification, and we’re sure we’ll hear about it from people who know more about sound than we do. But here goes.

Sound is measured and specified in deciBels—a tenth of a Bel—which is abbreviated dB. (Some components specify Bels; multiply by 10 to get dB.) Because humans perceive identical sound levels at different frequencies as having different loudness, various weighting schemes are used. The most common, A-weighting, is abbreviated as dB(A). There are also dB(B) and dB(C) scales, but those are not commonly used.

A sound level of 0 dB is defined as the threshold of hearing, a sound level that is just barely perceptible in the absence of any other sound. Here are some reference points:

• 20 dB – A very quiet library or church; rural background noise at night; the quietest possible PC with moving parts

• 25 dB – A whispered conversation; a very quiet PC

• 30 dB – Suburban background noise at night; a quiet PC

• 40 dB – A quiet conversation; a standard PC

• 50 dB – Normal household noise; a normal conversation at 1 meter; a loud PC

• 60 dB – Office conversation; a loud gaming PC or server

The dB scale is logarithmic, which means that an increase of about 3 dB doubles sound level. For example, if a power supply produces 30 dB and a CPU fan also produces 30 dB, running both at the same time doubles sound level to 33 dB (not 60 dB). Doubling the sound level again by running four 30 dB devices simultaneously increases the sound level by 3 dB again, to 36 dB. Running eight such devices doubles the sound level to 39 dB, sixteen takes it to 42 dB, and so on.

However, because of the way humans perceive sound, a 1 dB difference is barely perceptible, a 3 dB difference is noticeable, and a sound must be about 10 dB louder to be perceived as “twice as loud.” For example, if one computer produces 40 dB and another 30 dB, the first computer actually produces more than eight times the sound level of the second, but to human ears it “sounds” only twice as loud.

PC components differ dramatically in sound levels. For example, a very quiet hard drive might produce 25 dB, while another model may produce 30 dB or more. At idle, a standard 400W power supply might produce 40 dB, a quieter model 30 dB (half as loud), and a specialty quiet model only 20 dB (half as loud again). The same differences exist among other noise-producing components, such as CPU coolers, supplemental case fans, optical drives, and so on. Merely by choosing the quietest standard PC components rather than noisier alternatives, you can reduce the noise level of your PC noticeably.

The preceding three steps are the main issues to address in quietizing 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 putting the PC directly on your desk or the floor, put a sound-deadening mat between the PC 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 more 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 S-ATA models are the quietest mainstream hard drives available. 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 speed and are quite noisy, so replacing the fan with a passive device can reduce noise noticeably.

Choose a motherboard with a passive heatsink

The northbridge chip of modern chipsets dissipates significant heat. Most motherboards cool this chip with a large passive heatsink (see Figure 1-5 for an example), 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.

Use an aluminum case

Aluminum conducts heat better than steel, so using an aluminum case makes it easier to cool a system effectively. This has no direct impact on noise level, but it does allow you to use smaller, quieter fans than what you would need with a steel case. In effect, the aluminum case itself becomes a giant heatsink, radiating heat directly. Aluminum cases typically cost more than steel cases and their additional cooling efficiency is relatively minor, so this is probably the last step you should take in designing a quiet mainstream PC.

Note

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.

Designing a small PC

At the beginning of the millennium, some forward-thinking PC builders and manufacturers began to design and build PCs that were 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 other visual enhancements. Despite the customizations, LAN Party PCs are based on industry-standard components and are as capable as any standard PC. Chapter 5 describes the issues involved in designing and building such a system.

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 below 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 here 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 as well. 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 “barebones” 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.

Note

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.

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 370 Pentium III and even Socket 478 Pentium 4 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 that 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.

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 1-2. 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, and 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 minitower system whenever possible. If that’s too large, step down to a microATX system. And if that’s 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 tradeoffs are worth it—buy a barebones 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.