Sapphire 4870 won't turn on after reset - any ideas?

[thefreeaccount]

My Sapphire 4870 512MB was working just fine with my old motherboard (Biostar TA780G). After moving it to my new motherboard (Gigabyte 790XTA), I now find that my PC will not turn on after a hard or soft reset. All fans turn, but the three red LEDs on my Sapphire card all blink together in a repeating pattern (3 blinks - 3 blinks - 4 blinks - 4 blinks). There is no video output and I am sure that the PC will not boot - if I reset during this time, I don't receive the 'windows had a problem starting' menu. Turning off the power completely and turning it back on usually, but not always, allows the system to boot.

In addition, the ATI driver frequently crashes, both on the 2D desktop and in 3D gameplay, sometimes taking the system with it and causing a soft reset. This problem doesn't occur when the card is in my old motherboard.

My PSU is an 850W Seasonic S12D. I have tried using another PSU (Enermax 450W), but the problem persists. I tried purchasing a second Gigabyte 790XTA motherboard, which didn't fix the problem either. I tried RMAing the card, but the tech who responded insisted that if all 3 red LEDs blink together during the hung boot-up, the card is fine and my problem must be my motherboard or PSU.

I am at my wits' end. There are no BIOS updates for my card. I don't want to buy a new video card since the 4870 is enough power for me. Is there anything I can do?

 

[ito4u]

sounds like an incompatibility issue. Have you checked anywhere else? Maybe it's a chipset issue.