
Thermal grease, thermal gel, thermal compound, thermal paste, heat paste, heat sink paste, heat transfer compound or heat sink compound. These are all names used to describe the fluid substance used to increase thermal conductivity between two components. Often used in electronics to improve thermal dissipation by compensating for the irregular surfaces of two components(such as a processor and a heat sink).
Despite how flat the top of a processor or base of a heat sink look there are sure to be imperfections that will prevent the two surfaces from fully sitting against each other. The thermal compound acts as a filler to ensure that 100% of the CPU will be touching the heat sink.
Another purpose of the compound is to fill in all the tiny crevices on the
heat sink and metal plate that covers the CPU. To improve conductivity some extreme overclockers will sand down–also called lapping–the metal plate that covers their CPU as well as the heat sink in order to create two completely flat surfaces. This will allow you to use less thermal compound and the less thermal compound you are able to use the better the heat transfer from your processor to your heat sink. There are plenty of guides on how to do this–Google is your friend. If you have done it correctly you should have a shiny bronze surface on your processor that you can use as a mirror. From my experience I have only noticed a 2-4c degree improvement in temps on CPUs I have lapped which in my opinion doesn’t make the hours of time spent worth it. Not to mention you will void your warranty if you do this.
There are many different kinds of thermal compound ranging from silicon based to metal based. For the most part, metal based compounds have much better conductivity.
Is it worth it to remove my heat sink, remove the silicon compound and apply artic silver 5–or some other type of metal based compound–in its place? My answer–it depends on the individual. I have noticed a significant improvement moving from silicon paste to artic silver 5 with multiple processors. Currently I am using a Phenom II X4 Quad-Core clocked at the stock operating speed–3.0Ghz. With the stock silicon compound my idle temps were hovering around 42c which I felt was a bit high considering my ambient room temperature was 21c. I removed the heat sink, cleaned it and the CPU plate with alcohol and a cotton swab and applied a small dot of Artic Silver 5 to the center of the CPU plate–for instructions on your specific CPU view a complete list of guides here.
After going through about 5 heat cycles–allowing your CPU to reach max operating temps then completely cool helps the compound to settle–I was pleased to find that my idle temps had dropped a full 10c. This was a much better result than I was expecting. Usually I see a 4c-6c improvement but in this case I am assuming that the factory just did a poor job of applying the silicon compound.
So is it worth it? Ultimately it is up to you however in my opinion the 10-20 minutes you spend reapplying thermal compound is worth it. Especially in this case where for $5 and 10 minutes I gained a 10c degree temperature drop which allows for longer processor life or greater overclocking ability. With the silicon compound that came on my processor I was only able to overclock from 3.0Ghz to 3.6Ghz. With the artic silver 5 I was able to stably reach 3.9Ghz and had no issues after running stability tests for 10 hours.
So once again reapplying new compound is worth it in my eyes but that doesn’t mean I am encouraging you to do it! If you don’t know what you are doing you could really mess something up and I am not going to be responsible when you do. If you do decide to reapply compound go find a good guide on the internet since I have barely touched on what needs to happen to successfully reapply compound.