06-12-2019 07:51 AM
Very detailed post....I've read it twice and I'm sure there's still stuff that I'm missing.
Assuming you have both GPUs installed in x16 slots, then you're not facing a motherboard/slot bandwidth issue. Both cards operate at PCIe x16 gen2, and D30 can fully support that with the available x16 slots.
While everything you're trying to do appears to be within the specs of the GPUs, I still have some suspicion that you might be bumping up against the top end capabilities of the GPUs in trying to drive so many high res displays.
I've gone back and double checked the compatibility matrix for D30, and it does appear that we allowed mixing of these specific GPUs. That being said, I also wouldn't be surprised if you might be running up against some sort of limitation with mixing of Quadro and NVS. I would have actually expected the issues to track to the NVS510 trying to drive 4 x 4k screens rather than the K4000, so I guess it's good that that part of the config is working OK.
Have you tried eliminating the NVS510 and the 4 displays attached to it from the equation temporarily? I'm curious if the problem tracks specifically to the 3 display configuration you're trying to run on the K4000, or if the problem only pops up when you go for broke with all 7 screens.
At the end of the day, I think this is likely an issue with the Nvidia software/driver. From the system side, the cards are enumerating a running as they're supposed to. So it might be worth trying to play around with different driver versions. Fair warning though, these cards are on the older side, so I doubt there's been much in the way of driver bug fixes recently.
Lastly, you could also look at trying to update the VBIOS on the GPUs as well. I don't know the full VBIOS history for these GPUs, but it's probably worth checking to see if there have been any updates pushed out by Nvidia.