Originally Posted by Higgins
all you need is a BB sized drop in the center of the CPU.. then the pressure of the Heatsink will spread the thermal paste as needed. DO NOT spread it around prior to applying the heatsink.
I'm afraid I have to disagree with this statement. With dual core processors, it's actually advised to put a small vertical line straight down the center of the processor. Then spread it with a small piece of plastic or credit card (I cut a very small chunk of a container - like the plastic ones you get with memory), until the paste is a very thin, even layer. Get it almost as thin as possible without seeing through it. Oh, and make sure to mount the CPU on the motherboard first
The idea that the pressure from the heatsink will spread the paste isn't totally
a bad idea, but some heatsinks aren't completely flat, as with the IHS/CPU covers as well. If this is the case, it could cause an uneven or incomplete spread, which is not good. So I'd just do what I described above to make sure you are getting good coverage. I've always done it this way, and never had any problems.
Oh, and make sure there aren't any hairs or specks of dirt stuck in the paste before you put the heat sink on. If there are, carefully pick them out and re-smooth the paste.
And if you don't have a enough paste on, don't be afraid to apply a little
more. Just make sure it's very
thin. If you get too much on, no worries, you can scrape some off while smoothing it.
EDIT: Before you do all this, make sure you clean the processor off with some 90% pure (or higher) rubbing alcohol and a lint-free cloth. Q-tips can work, but sometimes leave fibers (especially the higher quality ones). I use a coffee filter, as it doesn't leave lint. Clean the mounting surface of the heat sink as well in the same fashion.
EDIT: Fixed dual core spread info above. (I was thinking of quads).