Ok I have a major problem with my rig ATM where: when I boot up it runs on 1 core of the primary card. The nv control panel is unavailable also. When I look in devices both cards have code 43 errors on all cores. (This code is for faulty hardware and driver has shut device down.) then I reload the drivers latest whql that I have been running for 2 mths and both cards work as normal on quad sli configuration. Games run as normal with normal gps and temps on all cards cores.
Now when I reboot or shutdown. Upon restate I get the same error and have to reinstall display drivers again. I have tested both cards in the primary slot and they are ok. It doesn't seem to be a hardware issue but that is the code popping up on them. Very frustrating so any help appreciated.
Cos

clear CMOS see if that helps?
Bios update?
something weird - but try and plug in your Monitor in a different card? or use a different plug to plug into your gfx card.

Im assuming youve got an Asus mobo? if so try the bios update first then the rest.

use them as a coaster like quacks did

LOL

Mate i have had similar trouble in the past with the tri card set up. I think it is corrupted drivers and the only way i fixed it was to go back to a restore point before it fucked up and uninstall the drivers and then reinstall. Have you had any BSOD's from Oc'ing your cpu lately
this is when they get corrupted. Sorry if that didn't make much sense im pretty smashed on some real good drugs at the moe.

Mate i finally found the problem after a lot of fucking around.....changing cards in diff slots diff drivers etc. with no success.....would work in single card but not sli on reboot.
Then found a thread about new realtek NIC drivers causing the issue on X58 boards...yes the ethernet driver lol. Rolled it back and tadaaaa no more issues...FFS! When i installed my new wireless router it must have changed the driver......

who woulda thought a NIC would mess wif ya GPU / PCI slots >:L