XFX HD 5850 Graphic card PROBLEMS!!

[big320488]

Hello everyone I been scrolling the forums tring to figure out what my problem is I, My XFX Radeon HD5850 Black edition card is causing problems. when i try to play a simple game like CSS after a few minutes i get a flicking and the screen turns into gray or brown vertical lines and most of the time freezes my PC, I tried adjusting down my GPU clock settings & memory clock settings. I jut downloaded and installed the latest AMD catalyst 11.7 and not sure what teh hell is going on!! any one have any ideas??? Plz help

 

[big320488]

FYI, My system is:

win 7 x64
Asus crosshair IV formula
AMD phenom II x6 1090T
cp-850 antec 850W power supply
XFX Radeon HD 5850 (part # hd-585x-zabc)
2 sticks of G.Skill DDR3-1600 PC3-12800 2gb

 

[big320488]

One other thing, My rig did have 8 gigs of ram in it but ever since i bumped it down to 4 gigs it freezes less and have less vertical lines of death screen that pops up. Is my Memory Sticks from G.Skill bad or is it all just the video card?

 

[big320488]

anyone have any suggestions??