Gigabyte Radeon HD6850 OC - screen glitches and black screen

[HunterMK1337]

Hi,

I just installed a nice shiny Gigabyte 6850 onto my main rig. It seems to run absolutely fine when I'm doing anything non graphically intensive, like browsing this site.

However, when I try and run any game, at any graphics setting, after about 30 minutes max I start getting black horizontal lines, screen splitting and total black screens after this time.

System specs:
Phenom II x4 840 @ 3.2Ghz
Radeon HD 6850
8GB RAM
800W Corsair GS800 PSU

As far as I can tell, I have more than enough power to run the card, and my RAM and processor are more than capable of running these programs. The games run fine at max settings and then suddenly will get the above graphical glitches. I have clocked the cards down from their pre-OC state to standard 775/1000 with no effect.

Any idea what is going on?

[Dark Mantis]

Hi and welcome.

It sounds to me like a temperature problem. It only seems to happen when the card gets hotter.

What temperatures do you have on idle and when running a game ?

[HunterMK1337]

Hi.

I wish I could tell you temperatures for the 6850. However, after a standard restart after a graphical glitch (As in Start->Shut down-> Restart, not a forced restart) the graphical glitches have spread not only to the Windows startup page, but also refuse to show a login screen so I cannot not log into my computer using the card.

I uninstalled the drivers for all graphics cards on my system, and reinstalled the 6850, with the same problems. The only change I made was to use MSI Afterburner to clock the card down to its standard clock speeds (775/1000). This worked for a short while, but then obviously has failed.

[Vladimir]

Vertical lines is not only sign of overheat, but also an energy outage. The GPU or even the CPU might not get enough Voltage on peaks (when activity of GPU/VRAM gets high)

Check PSU.

[Dark Mantis]

I uninstalled the drivers for all graphics cards on my system, and reinstalled the 6850, with the same problems. The only change I made was to use MSI Afterburner to clock the card down to its standard clock speeds (775/1000). This worked for a short while, but then obviously has failed.

Exactly what GPUs do you have on your system ?

I think that you need to try using your system as a standard configuration without any overclocking until you have found the cause of your problems.