Thanks to a leaky G5 I've netted myself a new dual-2.26GHz Mac Pro. I went ahead and ordered a Radeon HD 4870 from Apple, but I need another graphics card to go with it. It looks like I have a number of options: Second Radeon HD 4870 - This is an appealing option because it offers a lot of performance, but it's also prohibitively expensive and eats up two PCI slots between the heatsink and the power supply. GT 120 - The only supported option, but the Mini DisplayPort on the GT 120 and its anemic performance make it less than desirable, but it is single-slot. Radeon HD 3870 - Seemingly a nice compromise between options 1 and 2, but it would require figuring out a workable power arrangement (4-pin Molex to 6-pin PCIe adaptor off the 2nd optical bay?) and the reports of excessive fan noise are off-putting. It's priced similarly to the GT 120, however (when you add in the Mini DisplayPort adaptor) and actually provides two dual-link DVI ports while still maintaining the single-slot form factor. I went ahead and ordered a GT 120 since I suspect I can make use of a 3rd graphics card anyway, but am still wondering whether the 3870 would make a more desirable secondary card.