Originally Posted by kahloq
Both of these power supplies are insufficient. The +12 on the Q-tec is only 14a(even tho peak is 20a peak is NOT a sustained lvl, but peak..ie maximum at one time)
The Aopen also is too low as the +12 is only at 15a. You need a PSU that carries at least 18a on the +12(and not just a peak rating but sustained).
Wattage of a PSU isnt the tell tale sign that its a good performer. AS you said the q-tec is a 550 watt PSU but it cant carry the load. I have a 420 watt PSU, but its +12 rail is 18a sustained.
The TrueBlue that I've now ordered carries 22A on the +12V rail (Max, not Peak). That should be more than enough for a NU.