Im getting really bad screen corruption when my case is upright,getting occasional corruption when its on its side and getting none when its upside down.I know I shouldn't but when I was in my case while it was on if I pushed the graphic card slightely one way the corruption disappears and the other way it come back badly.Do you think the case being upside down the corruption is eventually going to reappear with the wieght of the card(its a ati HD 4850) by the way I tried changing slots and still get the issue.The thing is I didn't get the screen corruption until I got the new motherboard(and not straight away) so its hard to pin down which is the faulty part.
Its in tightly and is screwed in fully.I think the screen corruption is on a hardware level so I dont think a screen capture would help.I actually getting different graphical effects depending whats on the screen,on the black dos screen when its booting I get 2 big red bands made of tiny even spaced dots,on the bios bootup picture I just get evenly space tiny dots all accross it.In windows can quite remember but the mouse pointer gets a bit of corruption on it.When its gets really bad I get these small squares appearing all accross the screen in a sort of brick battern except more space apart.
Oh and Ill either get a VDU recover mode from the software that came with it and it will be normal again or it will completely reboot.
Clearly from the fact that the way the case is sitting changes things it's a connector problem. I've never seen any problems with the pci-e connectors, plus I've seen plenty with monitor ones, so first I'd try swapping out the monitor cable. Also try the cable in the other DVI slot on the card. If those don't have any effect then I'd try taking out the graphics card, inspecting the contacts to see if they've got any crap on them that might be causing a problem and cleaning them, then reseating the card. If none of that works, you'll have to test it with another graphics card, or test that card in another machine.
From your description though, my guess would be the problem has to be with the monitor connectors (haven't seen what happens with a DVI connector problem, but that sounds like what you'd get), I can't imagine you'd get a problem like that from the pci-e connector.