I came from using 2 970s in SLI to my current 1080. Also using OC'd 5820k. I had plenty of performance at 3440 x 1440P which is native resolution for my monitor. I ran mostly maxed settings, but had to turn down in some games a bit. What resolution are you running at? What card are you currently using? Like others say though, if SLI isn't scaling well, performance can drop considerably. Even at best, scaling isn't 100%, and you would use 250 to 300w to power the GPUs.