When I fill all 3 memory banks on my mobo, none of my 3D games work. Everything runs fine when only 2 of the 3 slots have DIMMs. All 3 DIMMs seem to be fine AFAIK. So, is it a problem with the video card, the mobo, or the memory? BTW, is there a program that can check the integrity of the RAM modules? Please PM me if you would like to reply, I don't read this particular forum too often.