If you stand in an emergency room of a hospital, then you will likely see a lot of sick or injured people. If you are in the technical forum of any game, then you will see a lot of people who have difficulty playing the game or having difficulty with hardwares. If you are in the forum of Nvidia/AMD's driver section, then you will find a lot of people with video card/driver related problems. See where I am getting at?If you read the nvidia thread, you will see the replicated the issue and a fix is in place..for next release. I get this error and so do lots of people on teamspeak that I play with. 4 cards is hardly a good representation of all the cards out there.
Some say OV fixes it. Some say disable HW acceleration fixes it. Some say rollback fixes it. Some say changing cable fixes it. Some say a new beta driver fixes it. Some say modding the inf file of the new beta driver fixes it. Some say updating BIOS fixes it. Guess what, OP was using 266.xx driver, which has absolutely nothing to do with the new 285.62 driver. In OP's case, the issue started out of the blue, not after a driver update.