Quote from: hairyteeth on February 13, 2014, 08:30:36 AM

Hi Guys,

I try to build a rig with 6 R9 290 Tri-x.

With windows or Linux, The computer just recognize 5 of them.
An idea to put the 6 on the same rig ?

ps : motherboard is Asrock probtc and my pci riser are on usb.

Thanks,

First step is to figure out what the problem spot is - card, cable, or mobo slot. I would.definitely suggest linux for all testing.

1. Identify the failing card by running 100% fan and noting the one that doesn't spin up.
2. Swap pci-e ports, try again. If a different card fails, it is then pci-e slot. Tell us which one.
3. Swap riser (change both 1X, 16X, usb, and power). If the other card fails, you probably have a faulty riser cable.
4. Finally, if 2/3 had the same card fail consistently, plug it directly into the PCI-e 16x slot, and leave all other cards unplugged. Does it fail to boot? Faulty card

Faulty USB risers are fairly common. They also seem to burn out sometimes if you have too many plugged into a single SATA or Molex cable.