CPUs - Part 2
Each Intel CPU has eventually been "cloned". The "clones"are not exact copies, and aren't necessarily 100% compatible. In fact, the word "clone" isn't even accurate,as explained below. But the non-Intel CPUs are an alternate choice, frequently are more powerful, and almost alwaysare cheaper.
Compatibility
The chance of less than 100% compatibility exists because the CPUscan't be physically identical, since Intel has their versions patented. This does not mean the Intel CPUs are actuallysuperior, but they are the most common, so they are the standard, and virtually all commercial software is compatiblewith Intel CPUs. Most software is also compatible with other brands, but not all; occasionally there will be aprogram that will fail on a non-Intel machine. This is probably because the software was written on an Intel-basedmachine and never tested on any other brand CPU.
Given that Intel CPUs are much more common, it is logical to assumethat any program is far less likely to be incompatible with an Intel CPU than with any other brand. However, weused an AMD for several years, and only had one program that proved incompatible. We really doubt that compatibilityis an issue any longer.
Relative power
Often you will see a clone CPU advertised as being more powerful thanthe Intel equivalent. Usually this is true. Why? It's the way they are rated. AMD, for example, uses the Winstone96 benchmarks to measure the performance of a new processor and rates it by the equivalent performance of an IntelCPU. As an example, if the AMD CPU gives equivalent performance to a Pentium 200, it would be rated a "PR200."Cyrix uses a similar rating method, and uses the "PR" ratings as well. For example, the Cyrix 6x86MX-PR233GPhas a performance rating PR233, meaning it's equivalent to an Intel Pentium 233. The Intel CPU has a clock speedof 233 MHz, but the Cyrix only has a clock speed of 188 MHz.
Here's the point: Intel CPUs are rated by their clock speed, whileAMD and Cyrix CPUs (and probably others) are rated by their performance, then labeled by comparison with the Intelstandard. This is not a bad thing, because it does give you a reasonable comparison. After all, you don't reallycare what your CPU's clock speed is; you care what kind of performance you get.
So how can a 188 MHz CPU out-perform a 233 MHz CPU? Basically, clockspeed is not the only factor. A CPU that can perform processing steps in a different sequence from their orderin the program will out-perform a strictly sequential CPU. The first CPU can issue a call for data from a disk,then do a lot of processing while it waits for the I/O to complete. Then, when the data arrives, the CPU picksup where it left off. There are other techniques which allow a CPU to predict which of various possible code brancheswill be used and call for disk data before the program actually requires it. Internal bus speeds can be different.Dual buses (one for input, one for output) can be used. There are many possibilities.
Cost
Right or wrong, cost is very often given more weight than any otherfactor. Intel CPUs cost more than other brands. Why? Probably because people will pay the higher prices. Thereare many people who won't even consider a non-Intel CPU.
As mentioned in Part1 of this article, Intel is apparently keeping their Slot 1 mountproprietary. To upgrade to a Pentium II, you have to upgrade your motherboard, but if the other CPU manufacturerscome out with a Pentium II equivalent that still uses Socket 7, you will be able to get Pentium II performancein your existing computers and the non-Intel companies will have a very strong edge over Intel. If Socket 7 simplywill not support Pentium II performance, the other companies will have to come up with their own mount, and wewill see a divergence in computers.
We believe that Intel is making a serious mistake in not licensingtheir new bus protocols to other CPU manufacturers. It resembles IBM's PS/2 strategy, in that it means that noother CPU manufacturer can use Slot 1, which also means that no one else can contribute to it. PC users have showntime and again that they want open solutions, so they can pick and choose from a wide selection of hardware andsoftware.
The most important points to consider, then, are:
- Cost (CPU price, plus whatever other hardware must be upgraded)
- Future upgrade (will you be able to upgrade again?)
- Performance (speed)
- Compatibility (will your applications run on it?)
You might want to wait and see what the non-Intel companies will doabout the Slot 1 situation, especially if you have hundreds of PCs, but remember how quickly things change in thecomputer world; there is always something better about to be released.
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Executive Software Europe
