Question Windows refusing to use specific graphics card

Nov 11, 2019
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Hi. I'm a long time lurker, first time poster. I've found lots of helpful tips here, so I'm hoping someone can help me with a rather strange problem I'm having.

I have two NVIDIA graphics cards, a 780ti and a 980t. I'd very much like my 980 to be driving my monitors, but I just can't get it to work! Well, it does, but not once the operating system loads. During the BIOS boot, the correct monitor is used but then after those start up dots for loading Windows disappear, bag! flicks to the other graphics card.

At the moment I have my 780 disabled, and have pulled the power cables. I thought this might trick windows into using the correct card. Wrong! My monitor is now being driven by the GPU on my CPU. I know the 980ti works because I've used it for rendering. That's what its job was. Perhaps somewhere along the line it decided it was dedicated for compute and now refuses to switch tasks.

So, anyone got any ideas about what's going on, and what I can do about it?
 

Mrgr74

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Hi. I'm a long time lurker, first time poster. I've found lots of helpful tips here, so I'm hoping someone can help me with a rather strange problem I'm having.

I have two NVIDIA graphics cards, a 780ti and a 980t. I'd very much like my 980 to be driving my monitors, but I just can't get it to work! Well, it does, but not once the operating system loads. During the BIOS boot, the correct monitor is used but then after those start up dots for loading Windows disappear, bag! flicks to the other graphics card.

At the moment I have my 780 disabled, and have pulled the power cables. I thought this might trick windows into using the correct card. Wrong! My monitor is now being driven by the GPU on my CPU. I know the 980ti works because I've used it for rendering. That's what its job was. Perhaps somewhere along the line it decided it was dedicated for compute and now refuses to switch tasks.

So, anyone got any ideas about what's going on, and what I can do about it?

Hey @jimzombie

  1. Disable the onboard IGP in CMOS.
  2. Remove the 780Ti
  3. Presto! or no? :)
Whats your PSU? Why do you have 2 different GPU's installed? If you have Win10 this isn't as much of a pain as Win7 was. If memory serves, it'll help if you had 2 cards in the same series, so say a 960 & your 980 for driver issues. Look on nVidia's site and see if their 980 drivers are the same as their 780 drivers.
 
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Nov 11, 2019
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It's a no.

You only need two of the same graphics cards if you want them to run SLI/crossfire. I don't need that. I only needed them for pure compute, so I bought the beefiest cards I could afford at the time.

I don't get it. I can boot just fine in safe mode. Uninstalled the drivers, restart, blank screen as soon as Windows loads. Somewhere along the line something is telling something else to do the wrong thing.

I forget the PSU ATM but it's probably an Antec gold standard 750 watt.

Thanks for the response, by the way.
 

Mrgr74

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It's a no.

You only need two of the same graphics cards if you want them to run SLI/crossfire. I don't need that. I only needed them for pure compute, so I bought the beefiest cards I could afford at the time.

I don't get it. I can boot just fine in safe mode. Uninstalled the drivers, restart, blank screen as soon as Windows loads. Somewhere along the line something is telling something else to do the wrong thing.

I forget the PSU ATM but it's probably an Antec gold standard 750 watt.

Thanks for the response, by the way.

Did a quick search and it looks like Win10 dropped support for older mix n' matched cards with their newer drivers. Was just reading a post on nVidias forums about using old drivers. Such as 341.44 for example or older. I also read that alot of people had better luck with running both an AMD & nVidia vs 2 of the same make tho I can't personally verify.
 
Nov 11, 2019
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Hmm interesting and weird. There's absolutely no reason for MS to do that. It's common practice for 3D artists to have mixed cards in their rig. Well I had both cards in there running. The 980ti was doing pure compute. That was on recent drivers. ATM I only have the 980 in there.
 
Nov 11, 2019
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I just switched it down to the second PCIe slot and that seems to have done the trick. Maybe that slot is damaged.

Ohhhhhh wait... installing the latest drivers again and now I've gone back to black screen. Grrrrr
 

Mrgr74

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The 780 isn't in the machine. I just moved the 980 down. Moved back. Still black screen after loading Windows.

The 980 has issues but the 780 does not? Possibly the 980 is bad? connecting via DP/HDMI/DVI? Try a different monitor or TV? Take the 980 back out & try just the 780. No issues? Do you have another system you can test the 980 in? I know you said it worked before, but if it's acting up now...

Whats the rest of your system? Everything updated & shipshape on that end?
 

Wolfshadw

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Try booting into safe mode.
The 780 isn't in the machine. I just moved the 980 down. Moved back. Still black screen after loading Windows.

Sorry. I was confused by this original statement.

Windows disappear, bag! flicks to the other graphics card.

and I missed this statement:

ATM I only have the 980 in there.

Please list your entire system specs to include the power supply (confirmed Antec?) and any connected displays.

-Wolf sends
 
Nov 11, 2019
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Alright, I just put everything back together the way it was before and it's all working like it was before. I just ran a geekbench to prove to yáll that I'm not crazy. My 980ti does actually crunch the numbers. I'll post the scores momentarily.

Sys specs are
mobo: Asrock h87 Performance
CPU: i7 4770
16gb RAM DDR3 666mhz
PSU: 750 watt Antec Platinum earthware
Win 10 current stable build
Everything is latest drivers and firmware


980ti.PNG
 
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Mrgr74

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Alright, I just put everything back together the way it was before and it's all working like it was before. I just ran a geekbench to prove to yáll that I'm not crazy. My 980ti does actually crunch the numbers. I'll post the scores momentarily.

Sys specs are
mobo: Asrock h87 Performance
CPU: i7 4770
16gb RAM
PSU: 750 watt Antec Platinum earthware
Everything is latest drivers and firmware


980ti.PNG

lol! Glad it's.... working? :) Gotta ask though, what "numbers do you crunch" Whats the primary use of your system?
 
Nov 11, 2019
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I primarily built it for 3D rendering. All those CUDA cores are great for rendering animation and images in Iray and Octane. Business took me in another direction the last couple of years so I decided to switch over the 980ti as the primary so I could better use the rig for gaming.
 
Nov 11, 2019
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I don't get the problem. For whatever reason the 980 just doesn't want to be boss :/

Thanks for the assistance so far guys. Eager to hear if anyone has any other ideas.

edit: I don't have another system to test the card in. I've got a little file server but that doesn't have the PCIe slots to put it into.
 
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