[RC5] Strange Keyrates
motion at es.co.nz
Fri Jun 19 20:09:36 EDT 1998
On Thu, 18 Jun 1998 13:02:11 -0700 (PDT), Keith Woodworth wrote:
>Whats the PR for? I have a 166+ and its a PR but have never
>about it till I just saw your post about it.
PR is a controversal rating that means equivalent pentium
performance. Eg a Cyrix 6x86 PR150 is equivalent to pentium at a
150 MHz clock rate (even though the 6x86 is only running at say
PR stands for performance rating, a PR2 rating means equivalent to
a pentium2. Eg my K6-200 is PR2-200, so it is much faster than a
pentium-200 and would be equivalent to a pentiumII-200 if such a
As you may know, Mhz is only a good performance rating if the chips
being compared are otherwise identical.
In the case of the K5/K6/6x86 etc they are very different to the
So some lab runs a bunch of benchmarks on all the pentiums. Cyrix
etc send their chip to that lab and they benchmark it. They then
look for the pentium with the same benchmark results to decide what
PR rating the Cyrix chip gets.
Note that the benchmarks run are primarily 'business oriented'
benchmarks. They do not heavily stress the FPU and they do not use
Quake FPS as part of the benchmark. Hence while a Cyrix 6x86 PR150+
may be slightly faster than a pentium 150 at business apps in
general, it's equivalent performance in any one application may
vary. (It is slower at quake).
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