Acually, my motherboard is dead, i'm changing it. I have no instructions. So when i removed the heatsink from the CPU, i 've noticed there is a cream between the CPU and the heatsink. Do you know how it's called and how to apply it?
It is a thermal compound - ( http://www.newegg.com/Product/ProductList.aspx?Submit=E... ) - there are many types but yes you need to use it - it fills in the surface of the CPU and Heatsink to make a good thermal contact so the heat properly moves from the CPU to the heatsink and without it you CPU will overheat.
One of the things you wanna watch for is curing time .... if that kinda thing matters to you ..... if you gonna install and go.....no issue. AS5 for example takes 200 hours to fully cure .... if after your build, you gonna test various OC settings / voltages etc, this is gonna wreak havoc with your testing as the properties of the compound change over time.
When we did my son's build, we raised CPU voltage up a bit (within safe limits) and ran overnight w/ core temps in the mid 70's. When we dropped it back down, temps at the old setting were 2-3 C cooler.
After this article was first published, there was an immediate backlash from some of the manufacturers listed in this review. The primary argument was the lack of cure time. Here is the Arctic Silver 5 recommended cure time instruction from the manufacturers web site:
"Due to the unique shape and sizes of the particles in Arctic Silver 5's conductive matrix, it will take a up to 200 hours and several thermal cycles to achieve maximum particle to particle thermal conduction and for the heatsink to CPU interface to reach maximum conductivity. (This period will be longer in a system without a fan on the heatsink or with a low speed fan on the heatsink.) On systems measuring actual internal core temperatures via the CPU's internal diode, the measured temperature will often drop 2C to 5C over this "break-in" period. This break-in will occur during the normal use of the computer as long as the computer is turned off from time to time and the interface is allowed to cool to room temperature. Once the break-in is complete, the computer can be left on if desired."
So by my estimation of this statement it would take almost a year of normal use to properly cure the AC5 compound, or almost nine days of continuous power cycles to meet their recommendation. Benchmark Reviews feels that this is a characteristically unreasonable requirement for any TIM product, and we do not support it. We want products that perform without the burden of sacrifice on our time, especially with some many competing products offering performance without this extra requirement.