If it is any consolation I have the same problem with a Surface Pro 3 in a dock. One of the mDP ports will not turn on if I have an additional USB monitor connected. Everything works fine under 8.1 and 10 until a week ago when one monitor refused to turn on.
A long shot I know but have you tried checking that both cards are well seated in their PCI slots?
I assume that a code 31 was displayed, for the other card?
Regards
UKMedia
Just checked on the Microsoft forums and some people seem to be having some success with driver version 347.25 with multiple monitors. Might be worth a try...
ooooh thanks, I'll try that
I've also tried all things NVIDIA in the task mgr to run in Compatibility Mode -8 and then I tried 7... no joy.
I'm gonna climb around back and swap the Video Cards, that'l sure as hell confuse it! ;-)
then, I look at that 347.25 driver after turning off all the Run in Compatibility Mode settings.
thanks UKMedia
It would also be worth running DXDiag from the search window, to see if that flags any issues. Good luck and let us know how you get on.
UKMedia
Back from climbing around under and behind the desk!
I swapped the Video Cards, now Winless 10 likes the bottom row of monitors.
Funny how the top left always shows the start of the boot process. This makes me think the card is working.
I ran DXDiag and took snips, basically it looked ok, although there were three displays listed, one with Win basic driver, and two with GeForce.
I uninstalled and erased the GeForce driver. Then I did a lot of searching in the Nvidia drivers, should have been easier, but I found 347.25, downloaded and it displays two lower screens and seems to crash like the other driver, that's the 347.25.
It used to start with 4 screens, I think it's going downhill...
In my search for more help I want back to where I got the 4 monitor setup, Falcon Trading Computers. I submitted some questions and with a couple hours got a call. He said all their customers get lifetime support and remotely fixed it in a half hour!
He said I had two drivers running. He ran a couple programs; BlueScreenView6 and DisplayDriver Uninstaller. He also uninstalled almost all of Nvidia. The installed the driver version before 358.50. So needless to say I'm even more a fan of Falcon, I had great experiences with them before.
Well prematureous solvedous, ya it didn't exactly work. After 5 hours, I lost two screens again.
So I tried all the stuff support did on my machine with the newest driver instead and still no joy.
Currently I've got it working and fingers crossed.
What I did, and support mentioned that two drivers might be confusing the OS,
I uninstalled one driver out of two from Programs and Features.
We'll see...thanks UK Media
Here's an update.
Went back to Falcon support, he diagnosed that one slot or card is going south.
This kinda fits, the unit works for 3 hours then fails when it heats up, not that hot though, just failing.
So, gonna try a GeForce 750, supposedly I can run 4 monitors off it and either the slot or the bad card is history.
Waiting for the post man... =8^0
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