I have an 8-core 2.8 mac pro, early 2008 model. I bought it from Apple with an 8800GT in the first slot, but I'm currently looking at adding a second card, which is where I get incredibly confused. I would like to run a pair of 8800GTs ideally - I know they won't run in SLi, but having the VRAM will be a help. Now, the 300w limit in the PCIe bay worries me - will a pair of 8800GTs go over this? The Genius Bar at Regent Street were about as useful as a snowball in hell at answering, babbling on about warranty crap rather than answering the question. I've heard that an 8800GT and a 2600HD work, but I'd prefer not to go down the different cards route - if only because Windows (vista64 to be exact) will most likely complain.