create a .bat file with any name in the same directory as nvidiainspector.exe
put in (for OC)
nvidiaInspector.exe -setBaseClockOffset:0,0,135 -setMemoryClockOffset:0,0,500 -setpowertarget:0,111 -setVoltageOffset:0,0,187500 -setGpuClock:0,2,1311 -setMemoryClock:0,2,3500 -forcepstate:0,2
and create another one (to go back to default)
nvidiaInspector.exe -setVoltageOffset:0,0,0 -setGpuClock:0,2,705 -setMemoryClock:0,2,3000 -forcepstate:0,16
PS: please adjust ALL parameters with thier corresponding Clockspeed etc. This is jsut a EXAMPLE!