I hade this happen on my old system, for me it was do to memory try taking all ram out and trying with 1 stick @ a time. Then try to swap your GPU it may be video ram problem. For me it was the ram on my GPU
If you dont have another GPU, try to uninstall the Drivers and reboot if it goes away its your GPU
I have checked the different ram modules like you suggested, not a difference at all. I`m also unable to enter windows. The screen goes totally black after the windows sound appears
see if you can try a friends GPU, if not a would RMA the GPU
Ya, if it was your cpu you wouldn't get any image at all so niklas_13 is probably right. I would say it has to be graphics card.