I have 24/7 voltages of 1.5. After extensive tests with my 1090t it seemed as though i got the s*** end of the stick, meaning needing more voltages to keep stable. I was only able to hit 4ghz at 1.5 volts. I think it might be because my MOBO is a crosshair III 790FX board. But my idle temp is 26c and my highest i have ever seen is 43c. But i cant even imagine 1.6v being to much, after all the 1090t ships with a 1.475v!? But at 1.5v its more of whether your mobo will take it.