5 x GPU problems

[electric_eric]

Hi,

I've been running a 6 x780ti rig for a long while without issues and have recently upgraded my video cards to 980ti.

I'm now struggling to get 5 cards running...4 works fine but when I add a 5th (in any configuration) I cant get past the bios menu.

I have a top spec machine which should easily support the full 6 x980ti's and plenty of PSU power, so I'm not sure what the issue is here.

Intel i7 6700k
GA-Z170X Gaming G1 motherboard
64gb Ram

[teknofreek]

Not that I know a lot regards this, but i7 6500k, is that right? I would have thought a 6500 series if any, was i5.. You don't mean 6700?
Dependant on what the mb is and the cpu, you may be running out of PCIE lanes and/or motherboard resources. (as related to the 980ti wanting a different allocation to that of the 780ti's)
Are you using the same MB as per the previous 780ti setup? If different, perhaps there is a different ability to configure the MB for all available PCIE slots..
I have an old gamer SLI based MB and it does not like having 3 gpus on the mb, and shits itself with the addition of a third gpu with unavailable mb resources.
I run an amfeltec splitter to overcome this limitation. Admittedly it runs the four external cards at pcie x4 off the MB to 4 lots of x1, the two internal gpus run at x16 each, but it seems for me no issue.

[electric_eric]

Sorry, yes that was a typo...my CPU is the i7 6700k.

I'm using exactly the same setup as before, just with the upgraded cards.

I have tried using a single GPU on the MB and the other 4 cards on an external frame but without any luck.

I've set up the exactly the same rig with 9 x 980ti on the pc at work (just a different MB) and that also works fine.

[electric_eric]

Any idea how many pcie lanes a 980ti requires?

My CPU supports 16 lanes apparently.

[electric_eric]

Apparently I need to open BIOS and free up some PCIe lanes.
Will let you know my findings.

[electric_eric]

So by changing the configuration of video cards and then letting the pc sit for 20 minutes to let it sort drivers out I've managed to get 5 cards working.

The problem I have now is with 6 cards, the pc will just not boot up at all now

Any ideas what to try next?

[coilbook]

i had similar problem. my old asus mother board could not handle more than 5 new 1080 cards,

Basically i have a netstor GPU box with 4 GPUs and it is connected to a PC with 2 more cards. It worked fine when i had 6 x 780TIs but after switching to 1080s every time I added 4th card into netstor box (making total of 6 including 2 new inside PC) PC would not come on. BIOS would not even load. I had to buy a new PC to support 6 cards, I think i had ASUS p9x79 https://www.asus.com/us/Motherboards/P9X79_LE/

[electric_eric]

Thanks for sharing that info.

I recently built a new pc and neglected to check the pcie lanes available in the CPU...schoolboy error.

Now the question is do I stick with 5 cards or sell my cpu and mb for something that can handle 6 cards???

[teknofreek]

What to do , a bit of a big question...
A suggestion is to use a GPU expander.. similar to what coilbook mentions.
Now, there are a few issues with what I mention.
Naturally the Nestor device is prhaps more expensive and may perform better, let's say more reliably.. with the latest opsys Window10 (1703) I don't know..
But prior to the Creators ed 1703, I had no problems running an Amfeltec splitter with 4 GPU's external to the PC.
(For some ungodly reason I can't get it to run with Win 10 pro 1703 and have gone back to using Win7pro).

From what I know.. filling the MB is perhaps the best way for multi GPU's and if you had for example a MB that could accommodate 7 PCIE x16 full length slots for 7 GPU's) it would be best.
But given you don't and are having issues with perhaps insufficient mb resources etc.. (has code 12 come up?) using a splitter or expander could be a good way to go as afaik they don't have the same drain on resources as a populated MB setup. For the cost around $350 or so... dependant on where you live, it may be a cheaper way to get going without the issue of selling your current MB etc.
Now I cannot say that it WILL work with your system, there are too many variables.. but I mention it as something to think about as an alternative to a new MB/CPU.

One other thing.... look in the BIOS and see if there are any non essential things you can turn off.. that is disable, hopefully freeing up some resources for the 6th card.

Sorry when tying the post I could not re-read your posts... some of this you have covered.. my apols..