I have SAPPHIRE Vapor-X Radeon HD 6870 graphic card, on factory settings, not OC-ed (2 years old, thermal paste changed twice, no dust – keeping it clean).
Motherboard ASUS P8Z68-V Pro. Intel Core i5 2500k, 8G RAM, quality PSU Corsair gold 750W. & 2x installed Windows 7 64x Ultimate (2 system partitions).
Graphics card run on max 70-71°C during longer gameplay. Max 40-41°C when idle. 1280x1024 screen res. Playing games occasionally only on weekends about max. 3-4 hours straight (not heavy gamer).
Few days back, during game play (WoW WoTLK) screen just suddenly turned black (without turning off screen by "no signal" state – screen is just on, but black), nothing I could do, just to reboot my PC.
After reboot, on windows logon screen appeared several horizontal white (or maybe bright gray) lines about 1, (1 and 1/2 cm) thick, and with 4-5 cm distance between them. (mouse pointer go over those lines not under them and number/count of the lines rises with higher screen resolution and vice versa). No lines during boot (windows loading screen and welcome screen Works fine).
Right after successful login attempt (typing right password +enter), screen turns black again and no response from PC. (same result on DVI as VGA as HDMI, same with lower/higher resolution by win safe mode, same on different screens).
If I try to shut down the PC from win logon screen (with lines) there is usual "windows is shutting down" massage and after that just "no signal" turn off of the screen, but PC wont turn itself off.
Fan on the card works fine & no temperature issue. Then I disconnected the card from PSU. After that I rerun system on that Intel graphics from CPU (core i5 support). Everything is working ok. Made backup of my files & reinstalled Windows (just in case, so I can perform "clean slate" test). Connected GC to PSU (btw PSU cable voltage is without spikes all within normal).
After clear win reinstall graphics card works (on any resolution). UNTIL...
Installed latest AMD for Radeon HD 6800 series driver & after reboot got immediately the same result with black screen & white lines. Not software/compatibility issue – tried on clean install of Windows.
Bottom line is: on pre-installed win 7 general/standard VGA driver (MS) my graphics card is operating normally, but after install of ANY version of manufacturers drivers (even through windows update) I get same white lines/black screen problem.
Is the graphics card bad? Any ideas why it is so weird?
Thanx in advance for any info.