Monitor connected to GPU1?
yes my friend, a monitor by HDMI cable, also connect the cable in the GPU2 and the same thing happens, the GP1 that is in the main pcixpress, I also try to boot without connecting any hdmi cable to the cards, and nothing, my motherboard has no integrated video
I think Windows uses more video memory on primary videocard. This causes your problem. And nothing will help there. You need integrated videocard or 1st GPU with 6G or 8G onboard...