Trouble with Multi-GPU setup for extra monitors

[ShadowWolf810]

Hi guys 

 

Got a new GPU, upgraded all my systems with the card that came out of the previous machine, had old but totally functional GPU sitting around. 

 

Got more monitors as well, did a bad job of planning out available ports. Figured, Well I'll just put the old GPU as secondary in my main system and use it for additional display outputs. 

 

It's all installed, properly connected, I've seen images on all 5 monitors (4 plus a projector) with the current config. 

 

When I first turned on my machine, both GPUs showed up in task manager. Monitors that were connected to GPU 1 and GPU 2 were working together at the same time, but then still 2 of 5 remained off. 

 

I figured I'd reinstall the NVIDIA drivers, but after doing so and restarting, GPU 2 does not show up in Task Manager, and neither of the 2 monitors plugged into are displaying anything, but now all 3 plugged into GPU 1 are displaying. 

 

If anyone has any advice on how to get the second GPU to be recognized in WIndows again, and get all 5/5 displays working at the same time, it'd be much appreciated! 

[ShadowWolf810]

GPU 1 has a 4 monitor limit per the specs. Which appears to be the limit here, but I don't understand why that'd affect the second GPU. 

 

I've done more testing and currently I've got 2 plugged into GPU and 2 plugged into GPU 1 and its working fine, minus not having my 5th one (projector) able to run at the same time. 

 

Does the main GPU's display limit really set the total amount a machine can support? 

[Mick Naughty]

What the hardware being used?

[ShadowWolf810]

38 minutes ago, Mick Naughty said:

What the hardware being used?

3090 GPU 1

1080ti GPU2 

Samsung G9 Main display at 240hz 10bit 1440p, plus a 165hz 1440p acer, and then 2 cheapest 1080p panels + hdmi projector. 

 

3090 says its got the 4 display limit, but really seems like a second GPU solely for displays should up that limit. 

[Mick Naughty]

1 minute ago, ShadowWolf810 said:

3090 GPU 1

1080ti GPU2 

Samsung G9 Main display at 240hz 10bit 1440p, plus a 165hz 1440p acer, and then 2 cheapest 1080p panels + hdmi projector. 

 

3090 says its got the 4 display limit, but really seems like a second GPU solely for displays should up that limit. 

That’s the limit per card. As long as there isn’t a limitation on that specific card based on the outputs used. 
No reason you can’t get 8 displays running. You don’t have anything effecting the lanes for the second gpu do you?

[ShadowWolf810]

5 minutes ago, Mick Naughty said:

That’s the limit per card. As long as there isn’t a limitation on that specific card based on the outputs used. 
No reason you can’t get 8 displays running. You don’t have anything effecting the lanes for the second gpu do you?

That's what I was thinking as well, but shouldn't be. I can double check the PCIe slot settings in BIOS but im running a 3970x so I've got more than enough lanes available. 

 

Seems like I have no problem getting the displays to show, its just I can only get 4. i.e I can plug 3 into the 1080ti and 1 into 3090, and see them all. But not the 5th. 

 

I had to delete the display driver after my post because it made the 1080ti not show up in task manager, and whichever displays were plugged into it not show up at all. Are there 2 seperate drivers? I tried looking at the 1080ti drivers, but it appears to be the same one for both

[Mick Naughty]

5 minutes ago, ShadowWolf810 said:

That's what I was thinking as well, but shouldn't be. I can double check the PCIe slot settings in BIOS but im running a 3970x so I've got more than enough lanes available. 

 

Seems like I have no problem getting the displays to show, its just I can only get 4. i.e I can plug 3 into the 1080ti and 1 into 3090, and see them all. But not the 5th. 

 

I had to delete the display driver after my post because it made the 1080ti not show up in task manager, and whichever displays were plugged into it not show up at all. Are there 2 seperate drivers? I tried looking at the 1080ti drivers, but it appears to be the same one for both

Yea its always gonna be the same driver. At least while they are still supported. If theres an issue with the card showing up theres another issue. May be why it still limits to four, as they are still being passed through to the main card.

[ShadowWolf810]

2 minutes ago, Mick Naughty said:

Yea its always gonna be the same driver. At least while they are still supported. If theres an issue with the card showing up theres another issue. May be why it still limits to four, as they are still being passed through to the main card.

Well the card is showing up currently when I'm back on the version of the game ready driver I had before I put the 1080ti in this machine. 

 

Now that I think about it, and checked the version, I'm using the current driver right now, both cards are showing up. I tried reinstalling the same latest driver, 457.51 with a fresh install before I learned about the 4 monitor limit. After reinstalling it, thats when 1080ti didn't show up in task manager. 

 

Shouldn't be any issues with the card. It's been in a working environment the last few years. Have 2 machines, before a few days ago, main rig was 3970x with 2080ti, and second one is an older x99 5960x and 1080ti. Then got my 3090, so 2080ti went into secondary workstation, 3090 into main of course, and 1080ti was free. 

 

PC did seem to hang on the driver install and then restart though so maybe that was the issue. But at this moment I'm running the current version, both GPUs are active. Can't go above 4