I just bought a nice new Athlon 64X2 6400, and it didn't come with a cooler, I didn't pay attention to that when I bought it, cause it was a retail edition, I just assumed it would. Anyhow, I'm set to replace an Athlon 64X2 4200, which did come with a fan/heatsink. My question is... can I just use the fan/heatsink that came with the 4200, will it provide adequate cooling?