the stock thermal grease is very, very thin. I remember when I first got my Athlon 64 3500+, the heatsink was huge and there's this tiny little block of darkish grey material on the bottom of it. I'm like, what the crap? That little amount is going to absorb all that heat from a 64-bit processor?! Sure enough, it works great. Once again, I have to gloat at my CPU temp: 28 degrees Celsius