Motherboard Gigabyte... Unknown model, it has AMD 770 chipset plus the SB710 south bridge with onboard 4200, DDR3. (Will grab the model later)
Memory 8GB Ram 1600 CL8 Corsair 4x2GB
Processor AMD Phenom II X4 965
HDD 4x500GB WD Caviar Black
Graphic Card HIS Radeon 2900XT 512MB
XFX 850W PSU
He just bought a new vga, a Sapphire 6850 it didn't work at all, the computer would only start from the onboard video which seemed somewhat buggy with colored lines everywhere. So we exchanged for a new one, now from XFX. Same issue, then again he returned it and got a 5870 for a little more. SAME ISSUE!
So... I got the card and tested on my own computer, a i7 870, Asus P7P55D-Deluxe, it worked like a charm! So now I got my Evga GTX 460 1GB and put in his system... Worked.. just fine. Same with a cheap 8400GS!
I have tried everything but both Radeons cards except for the 2900xt wont work on his computer, updated the bios, tried to clean the PCI-E slot and nothing. Is it a motherboard issue? On both VGAs it boots up from the onboard video and ignores the card in the PCI-E slot. The onboard video is a Radeon 4200, I have tried disabling it in the bios but I had to actually clear the cmos to get back on the onboard video since the offboard vga wouldn't work.
I'm currently using his new 5870 on my system and he has my GTX 460 lol, it's working just fine!
Any explanations? We're considering a new motherboard but it kinda sucks since it's a very current motherboard.