Multi-GPU Question

[The-Real-Link]

  Hi everyone,

  Simple question really.  So far in my rings I've tried mining with 4 6770s and also 2 5970s.  Either way whether 4 single GPU cores or 2 duals, this equals 4 GPUs.  OS is Windows 7 x64 home or pro depending on the system.  Can I mine with more than 4 GPU cores at once though?

  Now I was thinking I could run 3 GPUs in a system since the board has enough slots (not wanting to trust PCIe extenders with 5970s though they seem like an awesome idea).  I've heard though that the max GPUs in a system can reliably be four.  Is this true?  Obviously I know some people have 4 6990s crammed in a case right next to each other (so 8 cores) so I'm thinking that either it was just true say, under Windows XP or that that limit doesn't really exist any more.

  Would any multi-GPU miners care to share their insight on this please? 

  Either way should I want to put 3 5970s in, I would have to swap PSUs I think.  My rig has a Lepa G900 900w Gold PSU but I don't think it could quite handle 3 OC'd (not OV'd) 5970s.

  Thanks for the help in advance.

[1714017202]

1714017202

[antares]

hi there,

at least for linux there seems to be the slot limit only. my board is mining with:
2x unlocked 6950s
3x heavily oc'd 6770
1x 5850
1x 6850

I dont have any pci or pcie slots left(using pci->pcie adapters to max out the board), but everything seems to work fine, all cards are doing the expected HR.

[Swishercutter]

Windows= 8 GPU (Dual Gpu cards count as 2)
Linux= 10 GPU (I personally have not tested this because I do not run Linux)

Last August or so ATI updated the drivers to allow more than 4 GPU's (or 5...cannot remember).  Windows would recognize them but ATI's drivers would not allow them to be used.


Also, I have been using PCIe extenders with no issues for months...5 GPU/Machine with 4 extenders.

[goxed]

Running
5830, 5850, 6850, 6850 on a single motherboard since last 2 months 24x7 non-stop, no issues

[The-Real-Link]

  Cool.  Thanks for all the different perspectives here.  Well I'd have to rewire one of my systems now if I wanted to do a 3-card setup due to the original system's PSU being not quite strong enough for 3 big cards I'd think.  Other PSUs I've gotten now won't have that issue.  Good to know it's more of a preference with temps and noise as opposed to a hard limitation.  Yay for driver fixes.