before trying HyperSLI I was using driver version 327.23 on the single 760 card... since the modded drivers were only up to 320.18 i tried those with no luck. the only way the 760 could be used was to load the 660 first then swap cards around to get the 760 in the 16x slot. but no go . then I tried the 327.23 drivers again with the modded drivers installed . still same results as the 320.18 ugly wise but the 327.23 drivers allowed me to load them up with the 760 in the 16x slot and no floppin around.