I tried to update the BIOS. The board came with F2 and I flashed it to F1, still nothing. Flashed it back to F2. Hasn't been real stable with 5 cards either. 4 cards it runs great. Really thinking I got a bad board?

Not sure that would make a difference. The whole rig runs about 1085 watts stable with 5 cards and has 1500 watts available. Plus they hardly use any power until they start hashing so it seems like it would finish the boot cycle before crashing? Any other ideas? or does anyone else think this is a power issue? Really stumped and willing to try anything. I will get another power supply tomorrow if I can't get anything else to work.

Hello all

I have this setup

gigabyte 990FXA ver 4.0
AMD Sempron 145
4gb Ram
6 Sapphire Vapor-x R9 270x
2 Rosewill 750w PSU

16 x 1 powered risers and/or 16 x 16 powered risers

I can get 5 cards to hash, can't even get the system to boot with 6 cards plugged in. I am using SMOS linux BAMT 1.2 and tried 1.3 as well. All the cards are undervolted to 1.1v and run stable with just 5 cards running. Have tried many different riser combos and tweaked the bios settings endlessly. I have read that others have made similar rigs run with this mobo. What am I missing??

** edit - I can boot the system with 6 cards using a ms-dos bootable usb stick. and I can see all 6 gpus using atiflash. When I boot the system with 6 cards and BAMT i get to the BAMT screen, sytem does all the checks, then goes blank before the homescreen comes up.