Alright, I've had this issue for a little while and I've gotten fed up enough to ask for help. A few weeks ago, I had my GTX 660 replaced via EVGA RMA, and since I've acquired the latest functioning GPU, I cannot seem to get it to wake from sleep under OS X. There is NO wake from sleep issue under Windoze, oddly enough. Of course, it's a PC card, I am running 10.9.3 on my 3,1 with the card in PCIe Slot 1. Attempts to Fix: - Updated to the Web Driver - Repaired System Permissions - Ran Maintenance Scripts - Moved Card to PCIe Slot 2 - Switched Power Connector on Motherboard from 1 to 2 All to no avail. Would appreciate any suggestions or help. Thanks as always, -N ~~~~~~~~~~ Resolved. Bought another GTX 660, running two monitors off one, one off the other. No issues now. Weird.