Tbh, two wf 780's aren't ideal in sli if you have tight mobo spacing and a smaller case. A mix of one wf and a reference cooled model would work better for cooling. When spaced close together, due to the cooler design the top card gets much hotter than the bottom one. You'd be fine with a reference blower style card in the top slot and the wf in the lower slot where its fans wont be blocked.