I just spent two and a half hours turning my MacPro into the fastest Mac and the Fastest PC in the world. (Latter assumes non-SLi setup.) Here's the trick. . . You have to have an extra PCI-E card laying around, Mine was a 7950GX2 1Gig. You remove the whimpy 7300 from its nest on the bottom. As this card is pretty lame, it can sit in the top. There is a neat trick on the MacPros, the firmware controls the speed of the PCI-E busses. Take your doublewide PC video card and slip it into the bottom slot. Now, a good video card will need a seperate power lead, this is already taken care of. See, the kind folks at apple thought to include two four pin connectors for Graphics cards. Just find the correct dongle at any computer-centric electronics store, and go to town. Plug the power lead in and you're ready to go. Shore the case up, and make sure that all the cards are properly seated. Did I mention that you should have already installed windows??? It pretty much goes without saying, since anyone interested in this would have already installed boot camp and all. Ok, boot up the beast. Let it boot all the way into the Mac OS. There will come up a warning saying that the PCI-E configuration was changed, and it gives you an option to select a new speed configuration. Number one is the one we want, 16x on the bottom, and 8x for the anemic 7300. If it's set up right, close it and restart. This time, hold down the [opt] key. The boot selection comes up. The computer is running off the 7300 at this point, but don't worry. Select your windows partition, and boot. Windows will now go through it's traditionial horse poop, and tell you that new stuff is here and it wants to look for crap. Ignore it. Just download the GeForce or whatever drivers from your respective manufacturer. It will linstall, and you will need to restart again. Do so. Same procedure, [opt], windows, boot. Now everything should be working smoothly. Get any software you need, and you're ready to go! Working on benchmarks now, hoping for some killer scores. PCMark05 CPU: 9563 Super-Pi: 1M digits of pi in 7.68 Seconds, this is the fastest time I have ever seen posted on the internet. Screenies when i get back home.