Sapphire 7850 OC ED wont OC

I just bought my Sapphire 7850 OC Edition about 2/3 weeks ago and ive now decided i want to oc but.... when i overclock my core clock to mhz 1050 and my memory clock to 1450 mhz then run kombuster within about 10 seconds it starts to flash lines and then eventualy just crashes. Have i just been unlucky or is there something im doing rong? thanks for your help.
BTW im running catalyst 12.3

Update those ancient drivers first, then come back if you still have the issue.

Cata 12.3 is a very stable driver and not a issue at all. 12.7 may turn that PC into a instant crash machine, be prepared.

Ivy said:

Cata 12.3 is a very stable driver and not a issue at all. 12.7 may turn that PC into a instant crash machine, be prepared.

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Sure, I didn't mean for him to move to the beta channel though. 12.6 is stable as well, and between 12.3 and 12.6 there have been a few improvements for the 7 series.

There is no difference between 12.6 and 12.7, its almost same stuff with a few updates, it seems. Both got same issues on my system, crashing and DPI scaling issues, if someone know a solution to that problem (other than going back to 12.3) i like to know.