Book Suggestion
Choosing a CPU
Choosing a CPU for your homebuilt computer is probably one of the first things you will want to do during the planning stage. The CPU you choose will affect every subsequent decision you make about the components you choose, and will be a crucial factor in how your completed machine performs.
When choosing a CPU for a desktop, there are several factors to consider. The most important of these are speed, form factor, architecture, L2 cache, and reputation. Increasingly, computer builders are also concerned about power consumption and energy conservation.
CPU Speed
The speed of a CPU determines how many computations it can perform per second. Obviously, a faster chip can perform more computations. If you plan to use your computer for pretty routine, low-resource applications like surfing the web, word processing, and checking email, you can save yourself some money by buying a chip in the 4,000 MHz neighborhood. If you're a gamer, do video or music editing, or use your computer for high-end graphics or CAD/CAM apps, then set your sights higher and look for a chip in the 6,000+ MHz range.
Form Factor
The form factor of a CPU refers to several things, most important of which for the do-it-yourself computer builder is what socket it fits. You must purchase a motherboard that supports your processor's form factor. (Conversely, if you're upgrading an existing computer or using a mobo you already have, you must purchase a chip that your mobo supports.)
Architecture
Architecture refers to such things as the number of cores, the bandwidth, and the chip's internal circuitry. In general, multi-core processors outperform single-core processors, and some CPUs have internal circuitry that makes them perform better than other chips running at the same clock speed.
L2 Cache
The L2 (or Level 2) cache bridges the gap between the very fast CPU and the much slower system RAM bus (and the even slower hard drive) by anticipating and storing data right on the CPU itself. This dramatically increases performance at a given clock speed. With L2 cache, more is always better. Look for a chip with at least 1 MB of L2 cache per core. Although this significantly increases the cost of the CPU, it's worth the investment.
Reputation
As with any major purchase, do your homework before buying. Check Internet message boards to see how satisfied other users have been with the chips you are considering, and read the reviews often posted on retailers' sites.
64-Bit CPU's
Once upon a time, this page included a discussion about 32-bit CPUs. From feedback I've received, it seems that practically no one is interested in building 32-bit machines anymore, so I've decided to discuss only 64-bit chips.
AMD 64-bit Chips
As of this revision, 64-bit processors have pretty much become the norm. Among the most popular among do-it-yourself computer builders are AMD's Athlon 64
series.
Because all new operating system and application releases are expected to require or be optimized for 64-bit within the next year or so, it doesn't seem to make much sense not to choose 64-bit for your computer-building project. Even if you choose to install a 32-bit OS on your 64-bit machine for the time being, at least the machine will be hardware ready if and when you want to move up to 64-bit.
Just thinking about writing a section describing the 64-bit architecture and the differences between the various 64-bit chips in AMD's line gives me a headache, especially since the field is changing so rapidly.
Intel 64-bit Chips
AMD actually led the pack in the development of 64-bit processors, leaving Intel in the unfamiliar position of having to play catch-up. But catch up they did, with a dazzling selection of multi-core 64-bit chips with generous amounts of L2 cache. These chips, of which the Core2 Quad
The newer Intel chips also close the price gap between AMD and Intel quite a bit, which makes them more economically attractive for hobbyist computer builders. Intel also has their own line of high-quality motherboards
The performance and reputation of Intel chips, combined with their more competitive pricing model, has resulted in the company's products becoming more attractive to home-built computer hobbyists (most of whom traditionally favored AMD). In the end, those of us who build our own PCs benefit from better prices and more aggressive development.
- Components
- Processors
- Microprocessor History and Background
- Factors Affecting Processor Performance
- Choosing a Processor (This page)
- Processors
