overclocking the POwercolor HD4870 how hig can it go ?

[ASUSEN7900GTX]

WEll i tried ATT yesterady and had it 818/1100 but then bushes got wierd in Crysis warhead like bluish still no dots or so no lockups.

could it be stable at 810/950 ?

[Dazz]

Might be, you may find that you will have to increase the fan speed to clear up the artifacts, if not then you have hit your limit. However 810/1GHz should be fine. Having a 3rd party cooler will bring noise down and increase overclocking head room in most cases.