AS5 Applied to Cooler Rather then CPU

Master Shake

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Jul 14, 2007
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I am using the stock intel cooler and after I removed the stock paste from the bottom I applied a thin layer os AS5 to the bottom of the heatsink.

I covered the entire flat surface of the cooler


My temps seem fine, but was this a bad idea?
 

VinDSL

Diamond Member
Apr 11, 2006
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Generally speaking, yes, this is a bad idea!

Why?

The surface of the cooler is larger than the CPU, so the excess grease acts as an insulator instead of allowing the metal closest to the core to dissipate heat! That's why instructions tell you to apply grease/paste to the CPU only - and only a small amount!

Having said that, I usually put a V thin layer on both surfaces.

How thin?

Thin enough to read the lettering on the CPU... ;)
 

BonzaiDuck

Lifer
Jun 30, 2004
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I'm plus one for that, VinDSL.

There's nothing wrong with putting the TIM on the heatsink, but it should be limited to the area in contact with the CPU heatspreader.

AS5 is slightly capacitative, even if it isn't that conductive. One may not be asking for much trouble to have that stuff gathering dust or eventually blowing around inside the case, but then there's no telling how "much" is "too much," either.
 

Oerekum

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Sep 26, 2006
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Actually, the stock intel cooler footprint is smaller than the cpu surface. So it wouldn't matter much.
 

BonzaiDuck

Lifer
Jun 30, 2004
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ha! I had the stock cooler sitting on my table sans fan, and you're right.

It's always been the case since the socket-478 P4's that I don't even bother with the stock cooler. But they've gotten better as processor power has increased, and now I see a use for their 92mm fan.
 

Br3ach

Junior Member
Aug 27, 2007
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Right, that's what the instructions say basically that "it's more important to have proper contact in the area of the core(s), rather than a completely covered heatsink. Though I've always been wondering whether the amount I put on a Core 2 Duo (blob) / Quad (line) will actually suffice to spill out enough in order to cover the entire area of the core(s)....
 

Master Shake

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Jul 14, 2007
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Originally posted by: Oerekum
Actually, the stock intel cooler footprint is smaller than the cpu surface. So it wouldn't matter much.

That's what I thought, my temps seem ok so I should be fine until I order my ultima 90
 

BonzaiDuck

Lifer
Jun 30, 2004
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Originally posted by: Br3ach
Right, that's what the instructions say basically that "it's more important to have proper contact in the area of the core(s), rather than a completely covered heatsink. Though I've always been wondering whether the amount I put on a Core 2 Duo (blob) / Quad (line) will actually suffice to spill out enough in order to cover the entire area of the core(s)....

Some people have noted that their processor caps were slightly concave, but I've never seen a processor that wasn't perfectly -- or near perfectly -- flat.

I always use a credit card or razor blade to put a thin layer on the entire heatspreader cap, leaving a small dollop in the center for good measure. With AS5, one might be uncomfortable having it ooze from between the heatsink base and the cap, but the diamond-based pastes should leave absolutely no cause for worry. You could smear that stuff all over the mobo circuit traces -- it's just inert, non-conductive and non-capacitative.