Overclocking 7850

[willielikesmonkeys]

Hello all, 

Bought an MSI Radeon HD 7850 2G/OC Twin Frozr iii last year on a black friday and I never really got around to overclocking it. So Now I've got AfterBurner up on one screen and Kombuster up on another. Now, in Afterburner I set the Core clock to 1000 Mhz (over the 900 Mhz default) but when I run a stress test it only boosts up to 900Mhz (the factory over clock). Here is a screen of all the settings and stats, any ideas anyone?

 

(image is too big for LTT, sorry is dual monitor, uploaded to imgur instead)

http://imgur.com/MXthMUa

 

Edit:

To rule out thermal throttling I manually set the fan to 60% and the max temp went from 60 to 51. And still the same 900Mhz, so I'm pretty sure that isn't it.

[xAcid9]

Try max out the power limit.

[willielikesmonkeys]

Try max out the power limit.

No luck, nor with setting the voltage to a constant 1.2