Put windows 8 and you can do 6 cards.
Tried windows 8, saw 5 cards, gave error 43 for the 6th card. Took the 6th one out and couldn't run cgminer anyways. If I put it to I 10 or 11 It would maybe start for a moment, drive would crash a few times, maybe recover and then crap out, anything higher than that in I would just immediately freeze and lock up and then crap out. You would see the hash rate for everything jump 500 550 600 then freeze, everything crashes. I have a 1600w psu so I know power isn’t the issue, I was tried 13.1/28 and 12.8/2.8 in windows 8, both had the same result.
I've been in Ubuntu for the last 5 hours reading through all the documents on cgminer, despite what many believe about the system ram/gpu ram corrolation, either GPU MAX ALLOC PERCENT 100 isn't working for me or I need more memory. A high thread concurceny will crash all my gpus but one, and turn them off returning error 5 and disables them, but if I lower the thread corrurency to 1792 opposed to 21712 and turn the I down very low to 9/10/11 I can maybe get all 5 cards going at like 80-120kh/s (scrypt mining) so I'm very tempted to grab some extra dd3 memory and see if thats the issue.
But before I did that, I figured if ram is the issue than in theory I should be able to run only two cards both at full speed no problem. Pulled all the cards but two, one of them was in a pcie and would not post as enabled with hardware monitoring enabled, no matter what, removed drivers, reinstalled , rebooted, re initlized, changed cards and ports (different 1x port) same problem. moved over to a 16x port, no problem saw the card with hardware montioring enabled, Ok so I run cgminer, one card works fine, pulls 620-620, other card returns an error and doesn't hash anything. So I think the more ram theory is out the window.
Hephaestus, do you think you could make an image of your ubuntu 12,04 build that is currently running with x6 7950's? And upload it to a file storage site (ryushare, new megaupload) etc
Or provide any more details or insight to how you got that running? Out of curiosity how much RAM were you using? And you said you had it split on two PSU's ?
Thanks
I've got a rig with six 7870 XTs and one with three 7950s right now (both using this same motherboard)...and I'm actually having random reboots on the one with the 7950s.
Haven't nailed that down yet.
Both rigs have 4GB of RAM and are mining scrypt just fine.
From the beginning:
Booted Ubuntu 12.04.2 LTS from a bootable flash drive, then plugged in a 16GB flash drive and installed to it like a hard drive.
Ran all the system updates after it finished installing, rebooted.
Installed aptitude (personal preference), openssh-server, byobu.
Went to System Settings -> Additional Drivers and installed the beta drivers from there, rebooted.
Can't remember if I had to run aticonfig for anything at this point.
Copied over the a prebuilt cgminer (2.11.4) for x86_64 and a shell script from another mining rig.
Apart from the random reboots (which may still be a power issue), everything works fine.
Run lspci | grep VGA and it will show you all the graphics cards recognized.
Look in /etc/X11/xorg.conf and make sure they all have entries with the correct PCI addresses (unplugging a card will change other cards' addresses).
If they don't match up, try sudo aticonfig --adapter=all --initial and then reboot.
