I just recently acquired a 2008 Mac Pro with single 2.8GHz Processor. I want to upgrade to Dual 3.2's, but after searching more, I discovered there are separate heatsinks specifically for them. Is that even necessary? Also, best thermal paste? Also, I still need to get an OEM GPU, but if I don't hit it just right, I can't find one cheap. Best option for cheap (less than $45) OEM or Mac EFI equipped GPU? Also, here is a strange phenomenon my Mac Pro experiences. If I manually control the fan speeds, the system crashes, so I've left that alone and it works better. Also, last night it did it again when I tried to run a Blackmagic disk speed test. I was baffled. And after the screen shuts off, a few seconds later the fans all go to maximum speed. Could that be a sensor? I know it's not the hard drive, as it did it with another one I first put in the Mac to get it running. I did put a 750GB HD in and even a USB 3.1 card, plus 32GB 800MHz RAM, so I've made a minor investment, but paid next to nothing for the computer. I was told by the person I bought it from that it wouldn't post, but we've discovered that was wrong, fortunately. Sadly, the person he bought it from wouldn't tell him what was wrong with it.