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Topic: 6 cards on gigabyte 990?? (Read 703 times)

newbie
Activity: 3
Merit: 0
February 25, 2014, 03:25:59 PM
#5
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?
full member
Activity: 184
Merit: 100
February 24, 2014, 11:50:49 PM
#4
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.
If you can't get the board to boot with 6 cards, it is not a power issue. Power usage probably no more than 400w combined for boot.
As far as hashing goes you might run into problems if you can't balance the load evenly. 550w (if split perfect) on each 750w PSU, adding another 250w card can possibly overload one of them.

Try updating BIOS. Which board, UD3, UD5 or UD7? Pretty sure this is a BIOS or hardware limitation. Gigabyte support is usually very friendly, just email them with your issue and they might even try to reproduce it in their lab. One of their guys pulled up a Rev 1.x UD5 for me to give BIOS screenshots when I asked about CPU Load-Line Calibration settings before purchasing.  Cheesy
newbie
Activity: 3
Merit: 0
February 24, 2014, 09:40:17 PM
#3
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.
sr. member
Activity: 266
Merit: 250
February 24, 2014, 02:29:01 AM
#2
 2 x 750W seems low for your setup. I would do 3 on 850W another 3 + MB on 1050W.
newbie
Activity: 3
Merit: 0
February 23, 2014, 11:06:53 AM
#1
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.
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