This is my first build. I thought I did my research here, but I guess not. Before I tell you the issue, let me tell you my setup:
Gigabyte Z87X-UD4H motherboard (3 1x PCI-e and 3 16x PCI-e lanes)
6 Sapphire ATI Radeon R9 280x GPUs
4GB G.Skillz RAM
Intel Pentium Haswell CPU
2 PSUs w/ adapter:
1600w Rosewill Hercules (4 GPUs)
750w Rosewill Capstone (2 GPUs)
Every GPU has a powered riser.
Okay, so now to the issue. First I tried BAMT. I get the loading screen and it starts showing me all the services starting until it gets to GDM, then the screen goes black and becomes unresponsive. Tried fiddling with a billion BIOS settings, one GPU only, nothing worked. Gave up on BAMT.
Moving along, I decide to try my own Fedora install. I am a huge fan of Fedora. The LiveCD boots right off the bat. Everything working good until I go to install the latest ATI driver. I install it successfully. Hooray. I reboot and when Xorg tries to initialize...Bam! Black screen.
Okay, so after much tweaking I very sorrowfully give up on Linux and fall back onto Windows 8. I install Windows 8. Everything goes great. I get into the desktop and look in device manager. All my cards are detected, but as Radeon 7970s or just general Microsoft display adapter. I go to AMD's website and install the latest ATI Radeon drivers (13.12). Screen goes black. Same deal as last time.
So I decided to leave the driver alone in Windows. It detects my cards as an ATI 7970 series. Okay... whatever. That's fine. Problem is it only detects 4 cards usually. Well, once I got it to detect 5, but the thing crashes every time i try to start cgminer. Moving on to that problem. I got cgminer up and running and I actually had 3/4 cards running at a good hash rate (750kh/sec). Problem is that one card would hash at ~80Kh/sec. I figured I might have a bad card. So I started swapping em out and around, and seems its always the card that I have the display plugged into. Should this be happening? I can try the onboard video for my display I guess.
I am absolutely baffled here. I've been working at this for two days straight. It's like the drivers just won't initialize for more than one card. Do I need dummy plugs? 2350 watts of power is surely enough?!
On top of this, I got 4 Gigabyte Radeon R9 290s sitting here, waiting on the rest of the parts to build another 4 GPU rig. I decided to swap them out with these cards just to see if it would work. Sure enough I am getting the same damn black screen. These are all brand new cards from newegg. Should I RMA this POS?
Here is a photo of my setup:
https://i.imgur.com/yP2Mcml.jpgThank you for any help in advance.