Hi   I recently purchase a Sapphire 7970, the one with the 925mhz core clock (21197-00)

I have browsed these forums, and Googled for overclocking advice, as I seem unable to get more than 560khash out of it.

Am using cgminer with and without GuiMiner Scrypt.   

Settings are - 8192 threads   1 vector    Gpu threads 2    w 256    intensity 13

Then using Sapphire Trixx -   GPU clock 1085     Memory clock 1500     VDDC 1200     Board Power li 20     = 560khz

These seem to be the only settings my PC can handle, if I try to increase the clocks further, the PC freezes.

I have a good Corsair 850w psu, 8gb of ram and an i7 2600k cpu

Gpu temps are managed by Trixx, and they are fine.  Cpu temps are good also.

Not sure if it is worth persisting, or just settle for the 560?

Advice appreciated