I currently have an ATI 4870 card in this Mac Pro (late 2009). I use this rig for heavy Adobe Creative Suite 5 and FCP work. I use dual Apple LED 27" monitors. I'm about to order the 5870 graphics card upgrade from Apple, but before I do, is it possible to run TWO 5870 graphics cards? I am running into conflicting information and trying to get a definitive answer. If yes, do I need additional power cables and if so, which ones? Alternatively, I've read the 5970 card is essentially two 5870 GPUs on one chip. Will this be a better solution? I also want the cards to be drop and play ready/natively supported. As I rely on this computer for business, I'm not interested in continually chasing down third-party drivers. Replies and suggestions much appreciated! Thank you.