The key to applying thermal paste is simple - you want the surfaces to be clean, and you want only the MINIMAL required paste to get the job done. The most common mistake for beginners is to apply too much paste. You'll no doubt see this type of problem with stock heatsinks that were installed at factories; whether its for CPUs, Northbridges, or Videocards, the stock sinks tend to have huge gobs of regular white (non-silver) paste.

Step 1: Clean everything

You have to clean both the heatsink and the CPU die thoroughly. This is especially true if some previous paste or goop or tape or anything else is on the heatsink or CPU die. Note that we are saying the die - do NOT clean the whole CPU!!

Step 2: Apply a small amount of paste to CPU die

No matter what paste you are using, try putting just a small amount on the CPU die. For smaller Athlon XP and Intel CPUs you really only need something like the equivalent to half a grain of rice. For people with heatspreaders, you would need to use more. But start off with as little as you think would give a super thin layer. It's always better to have too little to start (because you can add some more after Step 3 and repeat).

Step 3: Spread the paste out

Using something with a clean edge, spread the paste out across the whole of the die. Most people use something like a credit card, stiff business card, or razor. Make sure not to scratch the surface if you use something sharp!!! How thin should you spread? 1mm thick is a good rule of thumb, but you won't be able to measure it so you're going to have to just eyeball. I like to make sure that the paste is so thin that it looks like it barely coats the surface. We have a FAQ on why should thermal paste the layer be so thin if you're curious.

Step 4: Install Heatsink carefully

Make sure when you install the heatsink that you don't accidentally rub the heatsink around, or angle it such a way that might smear the paste away from the cooler base contact area.

Additional Options

Some people suggest that after you clean the heatsink you apply a very, very small amount of paste to where you estimate the die will be, and then wipe it down until only a slight haze remains. I personally do this on all my permanent installs for peace of mind but there is likely no real benefit.

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