I want to get a 9800 GX2 but want to get one from NVIDIA and not from companies like XFX, EVGA, BFG or PNY. I want one made directly from NVIDIA. Where can I get one for my Mac Pro?



Actually NVIDIA does make first party cards becuz my mac pro has the 8800 from nvidia and t only says nvidia on it. it isnt from a third party.
OP, you'll have to shut down, take out the 8800 GT, plug in the 9800 GX2, and close the case to boot into Windows. The reverse is true of OS X; you can't just leave them both in.
I have run the BFG GeForce 9800 GX2 in my Mac Pro 3.2GHz Harpertown. It boots Vista 64 nicely and is screamingly fast running 3D games. However, I do have to physically remove it and insert a Mac compatible GPU to boot OS X. If I leave it in, put a Radeon 2600 XT in slot 2, and try to boot OS X, I get a kernel panic. But this isn't just about the power.