I have a 4,1 Mac Pro 2x 2.66 1x 128GB SSD 1x 750GB WD Black 1x 750GB Seagate 7200 1x 2TB WD Green 1x GT120 4 memory sticks 32GB Apricorn Velocity Solo -------- Initially I had the machine with 1GB (all slots used) and dual GT120 video adapters and the screens would blink constantly (as if someone would turn them off), sometimes at the same time and sometimes at random times. I took the computer to Apple store and they ran diag and could not see anything wrong and suggested to remove one video adapter. This has been fine for months and so one card was driving two displays. Yesterday I have installed Apricorn Solo adapter and moved the SSD there, and removed 8 RAM sticks and installed 4 larger ones. Everything was fine with the one monitor connected. I have connected second monitor (mini DVI I think is the port) and now that monitor will blink every few seconds. Is my PSU not up to the task?