A - defective hardware
B - severe thermal problems with your design
C - insufficient power supply
check all that apply. bamt will not work properly on this system until above issue(s) are resolved.
never heard of GPUs that have to wait before they will work again. I suspect you have some damaged goods there
B - I think the system is rebooting for high temp, but even after the cards are cool system still won't start. The only way I can make it start is by removing each card until I find the one with issues.
C - My rig has 3x 5970 (3x 350w = 1050w) and 1x 5870 (190w), so 1050+190+~200 for other components totals 1440w. I'm using 2x PSU BQT-PRO8-1200W, that gives me a total of 2400W. That should be enough, only way I coud see the PSU being the problem is that it's 2nd hand and could be defective but I think that's unlikely.
Could my rig be restarting as a result of some BIOS setting? I had one time where the system crashed and restarted. Then it wouldn't boot up and I did a BIOS reset and it booted normally again. That's why I suspect the motherboard could be causing all this.