gbm x86 stuff index




Undocumented K5 infoCollected by Grzegorz Mazur
The page was updated on 1997-05-14.
The AMD manuals state that there are several variations of K5, namely
models 0, 1, 2 and 3. As for today, model 3 (= K5-PR200) has not been
officially released, and considering the releas of K6, it will probably never
see the sunlight. My personal investigation shows something slightly
diferent. As far as I know K5s can be divided into 3 groups:

Old good SSA5, vel. K5 model 0, with CPUID signature of 0500 and 0501.
K5 model 1 with CPUID signature of 0511 and 0512.
K5 with CPUID signature of 05?4, which is model 1, 2, and 3 in single
chip! I had chance to test several such CPUs with production date
of 9707 and 9712, marked as PR133 (= model 1) and PR166 (= model 2). Here is a
short summary of my discoveries:

While clock multiplier pins are set to CLKMUL=1.5, the CPU identifies as
0514 = model 1
If CLKMUL=1.75, it says it is 0524 = model 2.
If CLKMUL=2, it appears to be 0534 = model 3 (PR200!) PR133
produced 9707 don't want to overclock for more than 30 minutes. PR166 produced
9712 overclocks nicely to 133 MHz = PR200.
The End
Copyright 1996 by Grzegorz
Mazur