4 x 290X problem

Hi all,

I have the following together-

Asus Z87-WS (latest BIOS)
4x XFX 290X
LEPA G1600
Ubuntu server 12.04.4
Catalyst 13.12

I have another build with the exact same hardware, works perfectly. This one, for some reason, gives me problems.

If I display an lspci, it shows the 4 cards. If I display a clinfo, it shows 3 cards, if I display od6config, it displays 3 cards.

I've formatted, reinstalled, and it did show all four cards in clinfo after the initial driver install, then I installed other things, od6config, etc, rebooted, and can't get more than 3 cards detected.

I've uninstalled (with --force) and reinstalled the drivers, same.

All power connectors are connected to the cards, and the three 6 pin EPS motherboard connectors are plugged in.

Ideas?