OK I recently purchased a second GTX 680 instead of dropping the extraneous dough for a 690 or TITAN. Upon installing it, my computer recognizes a second 680 is installed everywhere that matters (EVGA Precision X, Windows Device Manager, CPU-Z, even NVIDIA control panel...) here is a screenshot of all of the listed applications acknowledging my second GTX 680 http://postimage.org/image/arv9q9snx/
BUT, as you see in the picture if you look hard enough at the NVIDIA control panel. No option to enable SLI is present. JUST "Configure Surround, PhysX" with no mention of SLI.
Upon seeing this I started scouring the internet, I flashed my Bios to the latest version, uninstalled my display drivers, re-installed them, uninstalled them again, then installed beta drivers, switched the direction of my SLI connector, switched the PCIE 3.0 slots my cards are in, scoured my Bios for SOME option to enable SLI. NO LUCK. NVIDIA control panel REFUSES to offer the option to enable SLI. I'm losing my mind!!
Here are my specs:
CPU: Intel I7 3770K
Mobo: Asus Sabertooth Z77
RAM: 32GB GSKILL Ripjaws Z 240-Pin DDR3 2400
GPU: 2x EVGA GTX 680
PSU: Cooler Master Silent Pro M 1000W
PLEASE TELL ME HOW TO ENABLE SLI!!
**UPDATE**So it was easy as the fact that the first 680 I had was an original 2GB model and the new one I had purchased was a 4GB model. Different amounts of VRAM cards don't like to SLI
More about :sli option nvidia control panel gtx 680s solved
lol yes, that's why I said in the OP I changed the direction the bridge was connected. SLI can work without the bridge but its faster with it. I have tried all permutations with respect to the bridge: no bridge installed, bridge installed slot 1 forward, bridge installed slot 1 reverse, bridge installed slot 2 forward, bride installed slot 2 reverse. No luck. Same issue.