Powercolor 5830 problem

Hi all, Im having an issue with my video card coming up with weird mulitiple colored lines while playing battlefield bad company 2. Usually in the past i've wiggled the card a little bit and the lines would go away. Which leads me to believe that it may be the shear weight of the card putting pressure on the slot itself.. I have taken the cooler off, added some compound, monitored temps etc.. the temps are fine. 33 idle and about 62 max.. but lately "wiggling" the card isn't really working anymore.. sometimes im having to reset the pc due to the lines just not going away.. If anybody experienced anything like this any advice or suggestion would be very much appreciated..

my specs:
Case: Cooler master Rc-690 mid tower
Motherboard: Asus 785g evo atx
cpu: Phenom x4 955 black edition
memory: 4gigs of ddr3 1333 G Skill
power supply: cooler master 700w silent pro 80+ certified
harddrive: Western digital 640gb at 7200 rpms
video card: Powercolors 5830 dx11 gpu

Also.. The video card came with an over clock automatically set.. it was set as 850/1050
I have reduced their over clock to stock as 800/1000 but it was still the same result..