Hello All, I have a Late 2013 Mac Pro that I upgraded the CPU. Worked fine for a week then suddenly there was no display output on any of the thunderbolt & HSMI ports when I rebooted the machine. I've swapped out both GPUs (A&B) and the I/O card but to no avail. I know the computer is functioning as it chimes on boot up and I can SSH into the machine. Any ideas as to what to do next? Any help us appreciated.