Hickory Dickory Dock, What Happened To The Clock?

When it comes to discussing processor capabilities, clock speed may be old hat.

Well, will wonders never cease? Advanced Micro Devices has been saying for about two years, a company spokesman says, that clock speed isn't the way to delineate the essential properties of a microprocessor. So AMD processors have been referred to with model numbers for about that long.

And now Intel seems to have thrown in the towel, although Intel an Intel spokesman says that it's just the company's judgment that it's better to use model numbers rather than clock speed to talk about its processors, at least in the consumer-product arena.

Clock speed is, of course, still an important processor parameter. The faster a processor runs, other things being equal, the faster it can do its job. But, say both defenders of the new schemes for describing their microprocessors, other things just aren't ever equal.

And that means if you really want to understand which processor will get the job done best in a server that you want to buy, you have to understand a whole host of things about those processors in contention: clock speed, cache size, bus size, processor topology, memory topology supported, etc., etc., etc.And who wants to do that? Well, except for real hardware gurus, that is.

So, for example, in a press briefing on March 19, Intel, in discussing new processors, referenced the Pentium 4 Processor 560 with HT technology, and the Pentium M Processor 745. The processor numbers are intended to give persons buying a computer, whether a consumer or an IT professional, an idea of the processor's capabilities. Now exactly what these numbers mean is a little tough to decipher. Intel has a discussion of its processor numbers here. As a specific example, in the March press briefing, Intel gives a specific example of what the processor designator means. The Intel Pentium 4 Processor 550 supporting hyper thread technology runs at 3.4 GHz, has 1 MB of L2 cache and has an 800-MHz front-side bus.

A further example breaks down the numbers a bit. For mobile applications, you could have a Pentium M processor, a Pentium 4 processor or a Celeron processor. The first number in the descriptor for these processors would be 7, 5, and 3, respectively. There are similar characterizations for the desktop market.

Will this take a lot of education on Intel's part? "Oh, yes. It will take a lot of education. We are working with OEMs on this," the Intel spokesman declares.

AMD's scheme seems to be a bit easier to grasp. For example, on a Web page labeled AMD Opteron Processor Model Numbers and Features Comparison, the company lists a set of possible model numbers for its Opteron processors, and discusses what those numbers mean. So there's more of a direct reference to parameters like application performance (based, the AMD spokesman says, on actual application benchmarks) or power consumption, in these numbers.Both companies are trying, in these new product-numbering schemes, to get users away from the idea of using only clock speed in discussing processors. The AMD spokesman notes that the Honda S2000 sports car red lines at 9000 rpm, but a Dodge Viper, which has a much lower red-line speed will beat the S2000 in a quarter mile. So if you take redline rpm as analogous to clock speed for processors, it may not predict overall performance.

Intel says it's coming up with processor numbers in its products aimed at consumers, assuming that IT pros are more conversant with the technology involved in processor performance. But one could be forgiven for thinking that if the numbers meet with general market acceptance, the company could consider doing the same thing with its server processors.

And that could mean that soon, whether you go for a server platform from either of these companies, you'll wonder what happened to the clock. David Gabel, an electrical engineer, has been testing and writing about computers for more than 25 years.