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Building the Perfect PC by Barbara Fritchman Thompson, Robert Bruce Thompson

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Chapter 1. Fundamentals

The idea of building a PC for the first time intimidates a lot of people, but there’s really nothing to worry about. Building a PC is no more technically challenging than changing the oil in your car or hooking up a VCR. Compared to assembling one of those “connect Tab A to Slot B” toys for your kids, it’s a breeze.

PC components connect like building blocks. Component sizes, screw threads, mounting hole positions, cable connectors, and so on are standardized, so you needn’t worry about whether something will fit. There are minor exceptions, of course—for example, some small cases accept only half-height or half-length expansion cards. And there are important details, certainly. You must verify, for example, that the motherboard you intend to use supports the processor you plan to use. But overall, there are few “gotchas” involved in building a PC. If you follow our advice in the project system chapters, everything will fit and everything will work together.


Most compatibility issues arise when you mix new components with older ones. For example, an older video card may not fit the AGP slot in a new motherboard, or a new processor may not be compatible with an older motherboard. If you build a PC from all-new components, you are likely to encounter few such issues. Still, it’s a good idea to verify compatibility between the motherboard and other major components, particularly AGP video adapters, processors, and memory. The configurations in this book have been tested for compatibility.

Nor do you need to worry much about damaging the PC, or it damaging you. Taking simple precautions such as grounding yourself before touching static-sensitive components and verifying cable connections before you apply power is sufficient to prevent damage to all those expensive parts you bought. Other than inside the power supply—which you should never open—the highest voltage used inside a modern PC is 12V, which presents no shock hazard.

This chapter doesn’t cover the nuts-and-bolts details of assembling a PC, because that’s covered exhaustively in text and images in the project system chapters. Instead, this chapter explains the fundamentals—everything you need to prepare yourself properly. It examines the advantages of building your own PC and explains how to design a PC that is perfect for your needs. It tells you what you need to know and do before you start the project, and lists the components, hand tools, and software tools you’ll need to build your system. Because the motherboard is the heart of a PC, we include a “motherboard tour” section to illustrate each major part of the motherboard. Finally, because the best way to troubleshoot is to avoid problems in the first place, we include a detailed troubleshooting section.

Let’s get started.

Why Build a PC?

With entry-level PCs selling for less than $500 and fully equipped mainstream PCs for $1,200, you might wonder why anyone would bother to build a PC. After all, you can’t save any money building one, can you? Well actually, you can. In fact, there are many good reasons to build your own PC.

Lower cost

PC makers aren’t in business for charitable reasons. They need to make a profit, so they need to sell computers for more than they pay for the components and the labor to assemble them. Significantly more, in fact, because they also need to support such expensive operations as research and development departments, toll-free support numbers, and so on.

But PC manufacturers get big price breaks because they buy components in huge volume, right? Not really. The market for PC components is extremely efficient, with razor-thin margins whether you buy one unit or 100,000. A volume purchaser gets a price break, certainly, but it’s a lot smaller than most people think.

Mass-market PCs are inexpensive not because the makers get huge price breaks on quality components, but because they generally use the cheapest components possible. Cost-cutting is a fact of life in mass-market, consumer-grade PCs. If mass-market PC makers can save a few bucks on the case or the power supply, they do it every time, even though spending a few dollars more (or even a few cents more) would have allowed them to build a noticeably better system. If you compare apples to apples—a home-built system versus, say, an equivalent business-class IBM PC—you’ll find you can build it yourself for less, sometimes a lot less. Our rule of thumb is that, on average and all other things being equal, you can build a midrange PC yourself for about 75% to 85% of what a major manufacturer charges for an equivalent top-quality system.

More choice

When you buy a PC, you get a cookie-cutter computer. You can choose such options as a larger hard drive, more memory, or a better monitor, but basically you get what the vendor decides to give you. If you want something that few people ask for, like a better power supply or quieter cooling fans or a motherboard with more features, you’re out of luck. Those aren’t options.

And what you do get is a matter of chance. High-volume direct vendors like Gateway and Dell often use multiple sources for components. Two supposedly identical systems ordered on the same day may contain significantly different components, including such important variations as different motherboards or monitors with the same model number but made by different manufacturers. When you build a PC, you decide exactly what goes into it.

Flexible design

One of the best things about building your own PC is that you can optimize its design to focus on what is important to you and ignore what isn’t. An off-the-shelf commercial PC is by nature a jack of all trades and master of none. System vendors have to strike a happy medium that is adequate, if not optimum, for the mythical “average” user.

Want a small, quiet PC for your home theater system? There are three options. You can use a standard PC despite its large size and high noise level; you can pay big bucks for a system from a specialty builder that does just what you want; or you can build your own. Need a system with a ton of redundant hard disk storage for editing video or a professional audio workstation? Good luck finding a commercial system that fits your requirements, at least at a reasonable price. When you build your own PC, you spend your money on things that matter to you, and ignore the things that don’t.

Better component quality

Most computer vendors cut costs by using cheaper OEM versions of popular components if they’re “visible” and no-name components if they’re not. By “visible” we mean a component that people might seek out by brand name even in a prebuilt PC, such as an ATi or nVIDIA video adapter. Invisible components are ones that buyers seldom ask about or notice, such as motherboards, optical and hard drives, power supplies, and so on.

OEM components may be identical to retail models, differing only in packaging. But even if the parts are the same, there are often significant differences. Component vendors usually do not support OEM versions directly, for example, instead referring you to the system vendor. If that system vendor goes out of business, you’re out of luck, because the component maker provides no warranty to end users. Even if the maker does support OEM products, the warranty is usually much shorter on OEM parts, often as little as 30 to 90 days. The products themselves may also differ significantly between OEM and retail-boxed versions. Major PC vendors often use downgraded versions of popular products, for example, an OEM video adapter that has the same or a very similar name as the retail-boxed product but that runs at a lower clock rate. This allows PC makers to pay less for components and still gain the cachet from using the name-brand product.

It’s worse when it comes to “invisible” components. We’ve popped the lid on scores of consumer-grade PCs over the years, and it never ceases to surprise us just how cheaply they’re built. Not a one of them had a power supply that we’d even consider using in one of our own systems, for example. They’re packed with no-name motherboards, generic memory, the cheapest optical drives available, and so on. Even the cables are often shoddy. After all, why pay a buck more for a decent cable? In terms of reliability, we consider a consumer-grade PC a disaster waiting to happen.

No bundled software

Most purchased PCs include Microsoft Windows, Microsoft Office, or other bundled software. If you don’t need or want this software, building a PC allows you to avoid paying the “Microsoft tax.”

If you do want commercial software, you can buy OEM versions at a bargain price when you buy your hardware components. Buying a hard drive or a motherboard entitles you to buy full OEM versions of the software you need at a large discount. OEM software includes a full license rather than an upgrade license, so you needn’t own the product already to benefit from OEM software pricing. OEM software is one of the best-kept secrets in the retail channel. If you need Windows or Office, ask your vendor if they have OEM versions of the titles you want when you order components. OEM versions of Windows and Microsoft applications are “For sale only with a new PC,” but Microsoft takes a liberal view of what constitutes a new PC. Buying a hard drive, motherboard, or processor entitles you to buy OEM software.


The retail-boxed components you’ll use to build your own PC include full manufacturer warranties that may run from one to five years or more, depending on the component. PC makers use OEM components, which often include no manufacturer warranty to the end user; if something breaks, you’re at the mercy of the PC maker to repair or replace it. We’ve heard from readers who bought PCs from makers who went out of business shortly thereafter. When a hard drive or video card failed six months later, they contacted the maker of the item, only to find that they had OEM components that were not under manufacturer warranty.


Keep receipts together with the “retain this portion” of warranty cards, and put them someplace they can be found if required for future warranty service. This goes for software, too.


If you buy a computer, your experience with it consists of taking it out of the box and connecting the cables. If you build a computer, you know exactly what went into it, and you’re in a much better position to resolve any problems that may occur.


If you design and build your own PC, you can upgrade it later using industry-standard components. That’s sometimes not the case with commercial systems, some of which are intentionally designed to be incompatible with industry-standard components. PC makers do this because they want to force you to buy upgrade and replacement components from them, at whatever price they want to charge.


These designed-in incompatibilities may be as trivial as nonstandard screw sizes, or as profound as components that are electrically incompatible with standard components. For example, some Dell PCs use motherboards and power supplies with standard connectors but nonstandard pin connections. If you replace a failed Dell power supply with a standard ATX power supply—or if you connect the nonstandard Dell power supply to a standard motherboard—both the power supply and motherboard will be destroyed the moment you apply power to the system.

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