On Sat, 17 Jan 2004, wrote:

[snip]

I took off a 'Cooler One' HSF from my old XP 1700+, and looked at the copper
where it contacted the processor.
Nicely polished, but kind of uneven - not flat. Hadn't looked this close
when I installed it.
After hand-machining with a good flat file, I had removed the waves from the
surface.
Installing it, I achieved a temperature reduction of 5 deg. C.

Looking at the bottom of a couple of other aluminum HS, I found they were
not very flat, either. In this case they were all concave, i.e., the center
was deeper/closer to the fan than the edges.
I corrected this on one other HS as well. Cooler by 3 deg. C.
I was pleased by these results, but disappointed by the quality of the heat
sinks I had.

[snip]

I am not recommending anyone do this work as I have described above.
Only reporting my experience - FYI. This is my hold-harmless statement.

If you do choose to do this, please post with your results. Good luck to
all.

Here are some web pages about flattening (also called lapping)
heatsinks:-

http://www.neoseeker.com/Articles/Ha...uides/lapping/

http://www.sysopt.com/articles/lap/index3.html

http://www.fury-tech.com/modules.php...s&jump=lapping


As you say, working on the heatseak risks making it worse. The really
scary thing is flattening the CPU...

http://users.froggy.com.au/frogge/pe...apreport1.html

http://www.overclockers.com/tips31/