GTX280 or HD4870 video card in a Mac Pro?

Has anyone put an nVidia GTX280 or ATI HD4870 graphics card in a Mac Pro yet? I know that OS X drivers do not exist for these cards, but I'm interested in whether they work in a Mac Pro when it is booted into Windows. If I had a Mac Pro (thinking about getting one for a variety of reasons), I'd do all my gaming on it in Windows anyway. So having an extra gaming-only video card in the machine would be sweet. Does this type of setup work?|||I don't you'd be able to fit it in one...Not only that, these cards are largely Window based so you'd have to wait a while. I'm not really sure how Apple structures their motherboard, but from what I seen, I don't think you can customize it. I doubt there's even a PCI-E slot there or if the power supply will sustain either cards. Secondly...there's no such thing as an gaming only card. These cards are made for performance. You'd could use it for anything and it would improve the quality (ie. Photoshop) and speed.|||i tried to but my macbook just crapped its pants after