Messages in this thread |  | | Date | Sat, 21 Dec 1996 22:42:28 -0500 | From | Brett Hollon (BHOLLON) <> | Subject | re: AMD (again) |
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Sorry about the empty message I sent before.
In regards to the AMD 5x85-P75 chip Jim Nance write:
> What is it missing that makes it non-pentium-class? > > Jim
There are several major differences between the pentium class of chips and the 486 class of chips. Some of them are:
The 486 has a single instruction pipeline. The pentium has multiple instruction pipelines.
The 486 has a 32-bit data bus. The pentuim has a 64-bit data bus.
The 486 has a fixed 4k page size. The pentuim has 4k and 4M page sizes.
The 486 has a small set of specialized registers. The pentuim has a much larger set of generalized registers (which are aliased to mimick the 486 registers for multiple simulteneous instruction pipes).
The pentium has a superset of the 486 instruction set.
The pentium has specialized hardware for handling bus contentions in multiprocessor environments.
Because of these enhancements, the pentium outperforms the 486 about 2x1 at the same clock speed. That's why the AMD chip has to run at 133MHz to get performance similar to a pentium class chip running at 75MHz.
IMHO, the AMD gives you much more bang for the buck. One could argue that it greatly limits one's upgrade options, but I don't think that's such a strong argument. Motherboard technology is advancing very quickly, and even if one were to puchase a pentium now, the next upgrade will probably not be for quite some time (say a year), and by then the PPro will be the mainstream "affordable" chip. So, most likely you'll be wanting a new motherboard to go with your new PPro anyhow.
One big caveat that I would throw in is to make sure you get a PCI motherboard. VLB and pentium/PPro don't mix well and you may want to keep your cards when you go to step up your motherboard.
Hope that helps, Brett
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