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P233MMX Overclock on P90!
Editor's Note: I like this MUCH
better, because it involves NO soldering (other than the optional oscillator
upgrade)
From Terminaut- Tam Pham
Well, I've finally achieved success in the elusive arena of "overclocking"
a MicroChannel machine. I'm currently testing the "upgrade" using CheckIt
3 on the Server 95 in batch mode, and everything seems in order thus far.
Here are some preliminary information on how the mod was done.
I started with an IBM PC Server 95 with 256MB ECC RAM and a Pentium
90 processor complex (which I received from a VERY HELPFUL fellow MAD.
sufferer). The first step performed was to simply plug in a P233MMX chip
that was sitting on top of an Evergreen processor adapter unit. This worked
without problems, running the complex at 210MHz. Some of you may remember
from a while back that I ran my PC Server 720 at 233MHz. That was accomplished
using this same Evergreen adapter.
Jumper Settings
| CLK MUL |
P55C, M2, K6 (DUAL VOLTAGE) 3.5 (1.5) 3
|
P54C, K5 (SINGLE VOLTAGE) 2.5 2
|
| P1 |
OFF
|
OFF
|
ON
|
ON
|
| P2 |
OFF
|
ON
|
ON
|
OFF
|
| P3 |
OFF
|
OFF
|
OFF
|
OFF
|
| CLK VCC |
P55C, M2, K6 6X86L SOCKET 5 (5V) |
P54C, K5, 6X86 SOCKET 7 (3.3V) |
| P4 |
ON |
OFF |
| CORE VCC |
P54C, K5 6X86 3.3V
|
K6
3.1V
|
P55C, M2 6X86L 2.8V
|
M2 2.5V
|
| P5 |
ON
|
OFF
|
OFF
|
OFF
|
| P6 |
OFF
|
ON
|
OFF
|
OFF
|
| P7 |
OFF
|
OFF
|
ON
|
OFF
|
| P8 |
OFF
|
OFF
|
OFF
|
ON
|
DIP switch settings to run a 233MMX chip:
| P1 |
OFF |
| P2 |
OFF |
| P3 |
OFF |
| P4 |
ON |
| P5 |
OFF |
| P6 |
OFF |
| P7 |
ON |
| P8 |
OFF |
With that configuration working, I proceeded to change out the 60MHz
clocking oscillator. This was done by carefully desoldering the stock
unit
and replacing it with a 66.667MHz unit. I debated briefly on using
the
66.667Mhz versus 66.0MHz oscillator (the P66 complex uses a straight-up
66MHz clock) and ended up with the 66.667MHz just for "aesthetic" reasons.
Well, that's about all it took. The system is now running at 233MHz
and
seems happy about it. One thing I do want to do is replace the 60MHz
cache controller chip with a 66MHz version. My prior P90 complex (the DOA
one) had a 66MHz cache controller on it, but I sent that away.
I'm going to continue testing the system to make sure it is stable.
If I see
any signs of trouble I'll update the newsgroup. Right now it's sitting
with
the case open and running the CheckIt tests, but I'm going to get NT
on
there as soon as possible. I've got a lot of things going on, but I'm
definitely going to try to take pictures tonight to post to a web page
as
well.
Yippeeee!
- I'm way past MAD |