CPU heat sink staying cool - why isn't the CPU transferring its heat to heat sink?

[Dundonald]

Long story (background in thread "Newbie: 3 lots of CPU temp in
SpeedFan? 2 of them are overheating ..." from last week) but in short I
have an over heating problem, I've done some tests, and today I
realised that the CPU heat sink is not getting warm at all but by
contrast the much smaller motherboard heat sink does warm up.

So the question I have is, what possible scenarios could stop the CPU
heat transferring to the heat sink? I've pulled it off of the CPU to
check that there is the usual 'grey' solution there and there is. Any
help much appreciated on this one.

I originally thought there was a problem with the heat sink and fan but
to fair the fan is keeping cool a heat sink that is not even getting
warm in the first place, hence my problem with the computer just
switching off. So I need to figure out why the CPU can't transfer its
heat to the heat sink.

FYI I have an AMD Athlon 64 3200 CPU.

Thanks

 

[Paul]

Long story (background in thread "Newbie: 3 lots of CPU temp in
SpeedFan? 2 of them are overheating ..." from last week) but in short I
have an over heating problem, I've done some tests, and today I
realised that the CPU heat sink is not getting warm at all but by
contrast the much smaller motherboard heat sink does warm up.

So the question I have is, what possible scenarios could stop the CPU
heat transferring to the heat sink? I've pulled it off of the CPU to
check that there is the usual 'grey' solution there and there is. Any
help much appreciated on this one.

I originally thought there was a problem with the heat sink and fan but
to fair the fan is keeping cool a heat sink that is not even getting
warm in the first place, hence my problem with the computer just
switching off. So I need to figure out why the CPU can't transfer its
heat to the heat sink.

FYI I have an AMD Athlon 64 3200 CPU.

Thanks

You should use fresh paste, once the previous thermal interface material
is scratched up. Parts never mate the exact same way twice, so the
old thermal material should be cleaned off, and replaced with fresh
paste. The objective of the thermal interface material, is to get
rid of the "air gap" between assemblies, but at the same time the
material should be as thin as possible, to have maximal conductivity.
(When applying it, you want to use enough, so that enough oozes out
that you can see some paste wetting the edge of the heatsink and
processor lid. You don't want it to gush out, but you do want to
use enough to prove it has filled the gap. Using so little, that
it doesn't wet the joint, runs the risk of having an air gap.)

Ceramique:
http://www.newegg.com/Product/Product.asp?Item=N82E16835100009

AS5 (reported to cling pretty tight when you need to remove it):
http://www.newegg.com/Product/Product.asp?Item=N82E16835100007

Paul