1GHz Pentium III in an A20 - it works!

[pmx]

I've just managed to run a 1gig CPU in my old machine.
If you're interested, here's the way.

I have purchased a processor coded SL5TF.

After installing it, the laptop did not go past the bios screen. A bios upgrade helped, latest 1.13 Bios recognizes it properly.

However, it was impossible to work on the computer due to crashes. I realized that the CPU is overheating.

The fan control pattern from the Bios was not sufficient, so I installed TPFanControl. Here's my config:

Level=55 0
Level=60 1
Level=62 3
Level=66 7
Level=71 64

But that was still not enough. I cut a hole in the plastic panel between the keyboard and the screen and sticked some low profile radiator right to the factory CPU radiator. I have also removed the bars at the back of the cooler.

Now it works!

The CPU gets almost 90C under stress, so I will modify the cooling a little bit - but is stable.

A huge difference over the previous PIII-700, I get 84 instead of 64 CPU marks.
It is noticeably faster than a PIII-850, despite only 150MHz difference.

If somebody's interested I'll post pictures.

[huangj4093]

a20m was my first ibm thinkpad computer.I think that if you use the fan of the a20p'cpu the temp should lower.

[schen]

a20m was my first ibm thinkpad computer.I think that if you use the fan of the a20p'cpu the temp should lower.

Essentially, what huang said. Really, the best way to do this is to look at the HMM and find the part number of the fan that is spec'd for the 1.0Ghz processors. Then put that fan in and the machine should cool within spec. I'd also use something like Arctic Silver paste as well.

The chassis between the various As (A20,21,22) are virtually identical, so there's not a variation in structures that would acount for the differences in cooling efficiency other than the fan.

[pmx]

That's a good idea, the heatsink in the A20m is really small.