Adam744 :
btw I play a TON of planetside 2
increase mem clock by 20 and increase gpu clock by 15
run a gpu benchmarking software like unigine valley, or unigine heaven, see that there's no crashes\black screens, and repeat step one.
once you find steady settings, decrease both by 5.
you will hit a limit without increaseing voltages, but i suggest you dont mess with voltages, just to be safe.