Zotac Geforce GTX560 ti 448 core special edition (570 with one cuda core disabled, as a result native open CL and better power support in OSX)
did you do any editing of power management kext for this card? i use it (different brand though) to drive dual displays and my findings are, that when you use it with two monitors, the card doesn't go into lower power states when idle... works with one monitor though
