I think you will find that people that tinker with their computers tends to use thermal compounds rather than pads. While preassembled computers and boxed coolers comes with some sort of thermal pads. Compounds is superior to pads but needs some maintenance(cleaning and replacing).
Amd recommends the use of thermal pads if the cpu cooling is to remain fastened over long periods of time.
I use something called
Arctic Silver Ceramique. Which is nice, it doesnt lead electricity, has a nice viscosity and its very affordable.
