Specifically, I have an EVGA GeForce GTX 770 Superclocked 4GB, and an EVGA GeForce GTX 770 Superclocked 2GB. I am using them on an Asus P8Z68-V motherboard, which claims to support SLI. The cards are in PCIE slots 1 and 2, and both operate fine. However, the SLI option in the NVidia control panel never appears, and GPU-Z reports that SLI is disabled. I've updated the graphics card drivers and motherboard BIOS. I've also swapped the cards in their slots, and flipped the SLI cable around, to no avail. Is it more likely that these two cards will not SLI with eachother, or that the motherboard is lying about supporting SLI? I've searched the BIOS settings and beyond disabling integrated graphics and changing the PCIE16_3 slot mode to "1x", there are no SLI-specific options.