480gtx sli not working...

[Monkey Puzzle]

Hey, I recently added another 480gtx to my pc.

Specs are:

EVGA P55 FTW motherboard - currently in a 16x and 4x slot, but watercooled with an acrylic tube connector between the cards so don't want to drain the loop to change PCI-E slots right away if that's unlikely to be the problem...

2 x Asus 480GTX - different BIOSes

i5-750 at 4GHz

I'm not getting an SLI enable option in nvidia control panel. GPU-Z shows the second card idling when playing games, and 3dmark11 score is just over 6000 at the 720p setting on the basic version IIRC. Power output from a wall meter tops out at about 470W or so running 3DMark11 or firestrike.

I'm running the latest nvidia driver 331.82.

This is my first go at trying SLI... is there something obvious I've overlooked as to why SLI isn't working? Is it a driver issue, and if so does anyone know the last good set of NVIDIA drivers where SLI works for 480GTX SLI??

Thanks in advance for any help you can give!

 

[~Dockie]

One thing you haven't mentioned - Do you have an SLI bridge hooked up?

 

[Monkey Puzzle]

Yeah, have tried it on both SLI bridge slots on the cards, and turning it 180 degrees in case that makes any difference, but nothing... NVIDIA control panel has no SLI option under 3d settings, only 'adjust image settings with preview' 'manage 3d settings' and 'set physx configuration'.

 

[Deceptor]

Hm I thought the SLI menu showed up regardless? Since it's also where you select PhysX (if you're mad enough to put it on the CPU) and Surround settings.

Are both cards working separately? Try plug the monitor cable into the other card and see if it works.

If it's still not, could be a dead SLI cable?