Patrick wrote:

Stacey wrote:
Matt wrote:


We have a bunch of folks who have installed and removed heat sinks to
and from CPUs, along with the question of whether excess material is
squeezed out by the pressure of heatsink clamps.


From what I've seen, the excess (using plain 'ol white HS silicone grease
aka radio shack type) get's mushed out the sides no problem. Maybe some
thicker (arctic -insert your favorite low temp sounding metal-) type
doesn't do this? I've never had a problem with a rice sized blob, smear
it around a little and clamp the HS down. It always has a very thin layer
when removed later and never had any problem removing a HS with this
stuff either.

The stuff that oozes out can form a HEAT dam and hold IN the heat!

?? Since the heat is being transfered between the -top of the CPU- and the
-bottom of the heat sink-, that doesn't sound reasonable. How is that going
to stop heat from being transfered between those two surfaces? How much
heat do you think is being transfered out the side of the chip to the air
between the tiny gap between the sink and the CPU board?


Use thermal grease very sparingly, only enough to fill the micro voids
in the two surfaces, and not enough to keep the heat sink seperated from
the top of the cpu.

If there was enough staying between the top of the CPU and the heat sink to
"seperate" them, it wouldn't have squished out from between them! Given how
tight most clamps hold the heat sink down, the posibility of that
seperation happening is nil. Now maybe with some sort of "ultra silver" HS
grease it's so thick this is a problem? I wouldn't know about that one..

I agree you don't need to use any more than needed to cover the CPU and if
you insist on using conducting material you have to be very careful, that's
why I don't use that stuff. I've used silicone grease for over a decade of
building computers, overclocked etc and never had the first cooling related
problem.
--

Stacey