Hi, I've recently bought a new gaming rig with HIS Ice-Q HD5850 from Newegg. The graphics card worked fine for me for a few days then I decided to move my desk so this time I plugged in my DVI connector from my monitor to the other DVI port on my 5850. Then I noticed once I logged in to Windows 7 that the screen seemed to be constantly shaking. I thought my graphics card was damaged; when I switched the DVI connector to the original one I used initially, the shaking stopped and everything was fine.
I still requested an RMA from Newegg and received a second graphics card. I thought the problem would go away so I tried connecting my monitor to the same location as the troublesome port from the first graphics card. It turns out it still has the same problem on the same port and the problem goes away once I switch to the alternate DVI port. Then I've read some things about Electromagnetic Interference. I'm not sure if this is causing the problem but I don't have any other PCI express or PCI devices on my motherboard. I just have my power supply on the bottom due to Antec Three Hundred's design.
My spec is:
Athlon Phenom II x2 555 BE (x4 B55 3.5 ghz)
Antec Three Hundred Illusion
Samsung Spinpoint F3 1TB 7200 RPM
G Skill 4GB (2x2)
HIS Radeon HD5850
Gigabyte GA790 XTA UD4
Corsair 750W PSU
I'm using the latest driver from ATI. Note that one of the two ports works fine with no trouble while the other tends to give shaky output.
Some of the people I talked to told me I should get another RMA. I'm not sure what to do and I don't know what's the real problem. Any help would be greatly appreciated. Thank you.