Guide for Proper Application of Thermal Compound
First a little background as to why I am doing this: I recently had some issues with heat in my system. Since I never overclock my CPU, I have never had issues with heat from my CPU in the past so I went to look for possible problems. I asked around on these forums, and most people said that I probably applied thermal paste incorrectly so I went to find out the proper method. I couldn?t find any posts here explaining the proper application of thermal paste, so I decided to do this guide based on the advice of a few forum members, and a few reviews/guides I found on the net.
First off, thermal compound is not as thermally conductive as the actual heatsink, so if both the CPU and heatsink were perfectly flat, it would be best to mount the heatsink directly to the CPU without thermal compound. However, there are minor imperfections in the CPU heat spreader as well as the heatsink, which cause small pockets of air between the two when they are placed together, and these pockets are not very thermally conductive. That is where thermal compound comes in! It is designed to displace those air pockets with something far more thermally conductive. However it is not nearly as thermally conductive as the heatsink/heatspreader, so don?t goop so much on that the two aren?t touching each other ? it is only there to fill the small airgaps!
There are two commonly used methods for applying thermal compound; the first is to apply a small dollop in the middle of the CPU and let the process of mounting the heatsink to the CPU spread the compound out.
This theoretically pushes out the thermal paste reducing the amount of air pockets between the CPU and Heatsink. The second common method of applying thermal compound is to apply a thin layer of uniformly spread thermal compound on the CPU before applying the Heatsink.
This ensures that the whole CPU is covered with thermal compound, but it makes it more likely that air pockets will reside between the CPU and Heatsink. Because the purpose of the thermal compound is to displace those air pockets with something more thermally conductive, this method is close to using a heatsink without thermal compound.
Capt Caveman showed me a link to a MadShrimps review that compared the two methods (MadShrimp's Spreading it Thin TIM Roundup 2007
), and it clearly shows that dollop method works the best in practice.
Since we have already established that placing a dollop in the middle of the CPU and letting the heatsink spread it out when it is installed is the best method, this guide will just explain the intricacies of that method.
The first thing that you want to do is clean the CPU heatspreader and the heatsink underside. If you had thermal compound on the heatsink or heatspreader before, you should be able to wipe most of it off with a paper towel. (You may want to use a coffee filter or lense cloth to clean the parts to avoid leaving any lint) You can then use Isopropyl Alcohol or a cleaner such as ArctiClean to clean the rest of it off. You want to make sure that both surfaces are pretty clean before you mount the heatsink, because any left over compound may have trapped air behind it; reducing the effectiveness of the heatsink.
Next you are going to want to apply the thermal compound to the CPU. You want to place a small dollop (size varies depending on the consistency of the compound) in the center of the CPU. Do not spread the thermal compound. For Arctic Silver 5, Arctic Silver recommends a drop about ¾ the size of a BB(Arctic Silver 5 Application
), while Arctic Cooling recommends using a dollop about half the size of a dime for their MX-2 Thermal compound (Arctic-Cooling MX-2 Application
). Generally, the thinner the compound, the less you want to apply to the CPU.
Now that the thermal compound is on the CPU, the next thing you want to do is mount the Heatsink on top of the CPU. Be sure to lower it directly down on the CPU to ensure that the thermal compound spreads in a semi uniform matter. Before you secure the heatsink you should rotate the heatsink a few degrees in each direction to help spread out the thermal compound, if possible. Now secure the heatsink, and ensure that it does not move. If it does move, then it is probably installed improperly, and there are likely air pockets between the CPU and Heatsink. If that happens, pull off the heatsink and repeat the steps from the beginning.
Many thermal compounds require some time to cure. One of the most popular brands of Thermal Compound, Arctic Silver 5, advertises that it takes 200 hours to properly cure. You will want to check with the manufacturer?s documentation to find out how long you should wait before turning on the computer. If you are unsure how long you should wait, 1 hour is a pretty safe estimate. It may not be completely cured, but it will probably be cured well enough that you won?t damage your processor by using it. Just remember that you may get better performance over time.
Also, to clean the thermal compound off your hands, dish soap works pretty well.
Thermal Compound Recommendations:
I am by no means an expert in what thermal compounds are the best, but after reading a few review on the subject, I have compiled a list of them that have been well received. These are in alphabetical order. This list is subject to change as more reviews are done:
Arctic Cooling MX-2
Arctic Silver 5
Arctic Silver Ceramique
IC Diamond 7
Thanks to everyone that helped me, and contributed to this guide!
Please let me know if there is anything else I should include in here, or if you feel I have anything wrong. I just hope that this helps some people, as it was a little confusing to me when I first started looking into how to do this.