Moved the GTX260 GPU from the head node to n0005 and replaced n0005's PSU with a 650W unit. Take everything up again : Looks OK.

… and then after two hours had this excellent idea of moving the 3ware card to the newly emptied PIC-e slot. Only to discover that this 3ware card can only fit to a PCI-X slot. After a bit of cursing, put everything back to their original places, cursed a bit more, take it up, restart jobs.

Pipes froze, water started dripping in the terminal room [thankfully not in the cluster room (yet ?)]. To top it up, had three power failures back-to-back. Later in the evening started looking stable again (?) …