http://www.anandtech.com/weblog/showpost.aspx?i=603 Nehalem mac pro: Upgrading CPUs I actually finished testing the new Nehalem based Mac Pro several weeks ago, but in keeping up with tradition I had to see if it was possible to upgrade the CPUs on the new Mac Pro. Indeed it is, but it’s a bit more complicated than you’d think. Apple makes two models of the Mac Pro, one with two sockets and one with only a single LGA-1366 socket. The two socket model, often referred to as the 8-core Mac Pro, actually uses Nehalem CPUs without any heatspreaders. I suspect this is to enable them to run at their more aggressive turbo modes more frequently (high end Xeons can turbo up to higher frequencies than regular Xeons or the Core i7). The single socket model uses standard Xeons with heatspreaders, so there’s nothing special there. I actually managed to kill a processor card doing the CPU swap but I’ve taken the hit so you all don’t have to It’ll all be included in the article, I’m simply waiting on a replacement heatsink since an integrated thermal sensor got damaged during the initial swap. For now just know that it is possible to upgrade the CPUs in these things and it’s not too difficult to, you just need to know what to expect and to be patient. If you’re on the fence of buying today, opt for the slower CPUs and upgrade later if you’d like. And if you already have a good Mac Pro and aren’t terribly CPU bound, save the money and buy SSDs instead - in many cases the performance improvement is far greater. Once again, I’ll address all of this in the article itself.