Thursday, July 27, 2006

How to Choose the Right PC Components - Part 1 - the CPU and RAM

The CPU is often considered the brains of your PC, since it processes all the data that flies through a computer. To run your Windows OS, there are two brands of CPU available: Intel and AMD. Since Intel has the bulk of the market share out there, and in the interest of keeping this post under control, I’ll just discuss Intel CPUs. (please no hate mail, AMD fans!)

The CPU will normally have a model name and some specs after it. For example, in a typical business class PC you may see Intel Pentium 4 Processor 630 with HT (3.00GHZ, 2M, 800MHz FSB.) Why so much information? To break it down, Intel is the brand, Pentium 4 is the class of CPU, 630 is their model number, and most importantly those last bits of numbers are the specs. Currently Intel offers four classes of processors: on the low end, the Celeron; the mainstream Pentium 4 with HT (hyperthreading); and on the upper end, the Pentium D and Intel’s latest the Core Duo. Ok, there’s more than that, but we’re just considering mainstream desktop computers (not servers or notebooks.)

Intel’s latest technology “dual core” featured in Pentium D and Core Duo chips is like having two chips in one. This is an improvement to their earlier technology hyperthreading (or HT) which split your CPU into two operations (or “threads”). (Try an experiment: open up task manager and choose performance – do you see 2 CPUs listed, even though you only have 1 physical chip? You are using hyper threading. 4 CPUs: dual core.)

After the CPU’s make and model, you’ll typically see some additional specs: the megahertz, the cache and the bus speed. The megahertz is the actually speed of the CPU. However you have to take that number in context. The speed is only in comparison to other CPUs of the same family. The cache is onboard memory on the CPU. Intel’s current high-end CPUs have 2MB of memory. If the price of your PC is really low, you may have a CPU with only 512KB or 256KB of cache. Finally, the front side bus (of FSB) is the rate of transfer between the CPU and the rest of the PC. An Intel CPU will typically have a 533MHz or 800MHz front side bus, the later being a faster bus. If you compare computer systems for sale, a lower priced system (the ones advertised for $499 for example) will usually have the lowest end CPU, the ones with the slowest MHz, 533MHz FSB and only 256MB of cache. If you’re looking for a speedy system, pass these by.

The next item is RAM memory. Typically the type of memory must work with the motherboard and CPU, so once there’s not much room to make changes. The faster memory will only be compatible with the faster CPU. The average purchaser can ignore most of the memory specs (such as DRR2, the memory technology or 533MHz, the bus speed.) The bottom line? Simply look for the amount of megabytes (or MB) – no less than 512MB, 1GB if it’s in your budget. And don’t confuse memory with hard disk space. RAM memory is temporary memory your computer uses while your PC is running, while hard disk memory is permanent storage of documents and programs.

In Part Two of this post I’ll discuss what kind of hard disk to look for and what other options you may want to consider in a PC.

Mike Tanney
Product Manager
HLP Associates, Inc.
www.hlp.net