How much i can overclock my GPU?

[adamking]

Hello, my GPU have standart: 625MHz on Core and 993MHz on Memory
GPU: Sapphire ATI HD 4850 (512MB)
PSU: 420W
CPU: AMD Athlon X2 340 (Overlocked to 3.6GHz from 3.2) using EasyTune 6 via Gigabyte App for my Gigabyte Motherboard
How much i can OC gpu? I had 700 on Core and 1030 on Memory and sometimes video crash but Sound running, in game i still can control the game but display on monitor is black..... If i unplug DVI from GPU and plug it back, display not work. Only hard reset button help to get display working
Thanks for help guys
Cheers Adam

 

[scout_03]

your gpu could not handle this high overclock you need a new one for better speed .