Why is one of my GPU giving low hashrates? *Newbie*

[Electrolytez]

First off, I'm new to the whole scrypt mining and just build my first mining rig with 4 Sapphire R9 270x. Issue I have is GPU 0 is giving me between 10-50 hashrate with 4-14 HW. I was able to run all of them fine at around 485 k/hash. I've tried setting the Intensity and TC lower but that didn't work.

[lewisg]

watts of psu?

[fenghush]

GPU 0 is rendering the GUI from the OS so some of its power goes there.

[Electrolytez]

watts of psu?

Enermax MAXREVO 1350Watt

GPU 0 is rendering the GUI from the OS so some of its power goes there.

Still new. How do I make it not render it from the OS?