Quick! What's the difference between the Pentium, Pentium Pro and the new Pentium II microprocessors? Not many people, including those who use computers every day, can answer this question off the top of their head. But many of these people have to spec and buy PCs for a variety of applications. Add different CPU speeds, MMX technology and PC systems built with competitive chips from Cyrix and AMD to the mix, stir gently, and you'll pour out an often bewildering set of options. (For more details, visit ZDNet's new Webopedia Web site.)

A case in point: I design and build Internet Web sites for a living. I'm often required to assess the performance of a Web site running on a certain machine and specify hardware for new sites. Earlier this year, one of my clients -- a premiere job posting site on the Web -- had a problem. Traffic to their Web site was taking off, generating a great deal more traffic much sooner than originally anticipated -- a good problem to have if one is in the Internet business but not good for impressing the new job seekers coming to the site. Users were beginning to experience significant delays while searching for jobs, which can mean death to a job search Web site.

Lots of Head Scratchin'

The Web site was hosted on a low-end server provided by a prominent computer manufacturer as part of a partnership deal with my client. With the assistance of the site's systems administrator and some of the engineering team, we began to study the machine's hardware and software configuration to figure out how we could improve the server's performance. Even though the Web site was not on a typical desktop PC, the process we went through and what was learned along the way is applicable to any desktop PC or server hardware specification process.

The machine had dual 200MHz Pentium processors, 128MB of RAM, two 4GB hard drives and Windows NT. To most of us involved, raised on early PCs (anyone remember the excitement when the IBM XT came out?) and their predecessors, this server was raw power personified -- not some dog machine in need of an overhaul. The size of a small office refrigerator, it represented computing power that 20 years ago would have filled our entire offices.

We overcame our awe and started running tests, tried different configurations, tweaked software and generally did everything we could think of that might debug this machine. We called the manufacturer and consulted with one of their experts over the phone and tried the things he recommended. We even installed new RAM, which brought the total installed RAM up to 197MB, but nothing seemed to work.

Then the unthinkable occurred. The machine completely crashed. (Any of this sound familiar?) In desperation to quickly get the site back online, we grabbed the most powerful machine we had on hand and put the entire Web site onto it. The new machine was a brand new, single processor Pentium Pro PC running at 266MHz with 128MB of RAM. The site ran better on this desktop PC machine despite less RAM and one less processor. We were tempted to leave the Web site on the Pentium Pro PC and use the dual-processor server for something more useful