Diagnosis help needed

[narsbars]

I have a brand X 550 watt power supply. Tforce 570 SLI, AMD 6400, EVGA 8800 gts with no OC, one DVD, two HD.
All this is inside of an XCLIO wind tunnel. At times the PC will suddenly completely shut down and will not restart for a couple of minutes. I checked the CPU cooling, all of the case fans and filters etc.
Long story short: When I unplugged three of the case fans (120s) the PC runs quiet and will game for hours with no problems.
Bad fans? Junk Brand X psu? How would I go about testing?

 

[Nenu]

Unplug other things instead of the fans and see if it improves.
Try loading the PSU about the same but without those fans and see if the same thing happens.
Careful not to load the PSU too much, they can go pop when at their limit!

 

[device manager]

Please list the actual make and model of the psu.