Also my diagnosis does not tell me that the PSU cannot sustain the power load. The PSU has been bought as what I thought was with enough headroom. It is designed to deliver 20A at 12V. The drives use 13A at 12V when they are stressed.

Two points occur to me:

(1) The PSU may be designed to give 20A on the 12V rail, but that doesn't absolutely guarantee it does.

(2) The drives take 13A. Are you taking into account anything else that might also be running off 12V? This rail is plumbed through to the PCI/ISA/whatever else slots as well, and some cards do use it. Also, what supply do the 7 fans use?

Patrick

Opinions expressed in this email may contain up to 42% water by weight, and are mine. All mine.