Question Can't run dual GPUs on a Maximus X Formula?

May 22, 2022
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I thought my Titan XP was dying, so I bought another used one bc it's what I could get. I've since found out mine is fine and so decided to run SLI.
However, my Maximus X Formula (9900K, BIOS 2701) will not [] detect both cards simultaneously. Both work fine on each of the two slots on their own, but no matter which one I put on top, they won't work in tandem, won't appear in NV Control Panel and won't appear both in BIOS. When I connect the EVGA GHB SLI bridge thst I have, the top one is detected in x8 speed. When I take it out, the bottom one is detected, but never both.

How would I go about troubleshooting/fixing this?
 
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DRagor

Illustrious
Rip that's weird. I have EN manual. E132427 on the top-left, First Edition October 2017 (Idk if that's useful). I'll check the box later for the SLI logo, too.
Clearly both those versions can't be right at the same time. And no, there are no different board versions either. One description must be mistaken. That said in either case the board should at least detect both Titans. Check the BIOS settings if there is anything that would lock 2nd slot when 1st is used for GPU.
 
May 22, 2022
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Clearly both those versions can't be right at the same time. And no, there are no different board versions either. One description must be mistaken. That said in either case the board should at least detect both Titans. Check the BIOS settings if there is anything that would lock 2nd slot when 1st is used for GPU.
The board should support both because it seems to interchangeably choose whichever (1st or 2nd slot) whenever it wants. When they're both in and connected, sometimes it uses 1st for GPU, sometimes it uses the 2nd. It's got me baffled.
 

DRagor

Illustrious
The board should support both because it seems to interchangeably choose whichever (1st or 2nd slot) whenever it wants. When they're both in and connected, sometimes it uses 1st for GPU, sometimes it uses the 2nd. It's got me baffled.
That's easy to explain. When board starts post it sends query to all connected devices, then initializes all that answer. Except in your case it initializes only GPU that responds first and ignores the other one. That's why it is random which one is used. Does the Windows Device Manager sees only one of them at a time?
 
Reactions: Phaaze88
May 22, 2022
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That's easy to explain. When board starts post it sends query to all connected devices, then initializes all that answer. Except in your case it initializes only GPU that responds first and ignores the other one. That's why it is random which one is used. Does the Windows Device Manager sees only one of them at a time?
Yes! Device Manager and NV Control Panel only see one at a time. I did notice the first time that I installed both that I ran DDU in Safe Mode, and it briefly saw both. After the restart only one was detected, and then I clean installed the newest Nvidia driver.
 

DRagor

Illustrious
Yes! Device Manager and NV Control Panel only see one at a time. I did notice the first time that I installed both that I ran DDU in Safe Mode, and it briefly saw both. After the restart only one was detected, and then I clean installed the newest Nvidia driver.
That's interesting, it could suggest there is a driver problem. Can you go to safe mode again (without uninstalling driver) and see if both are seen?
 
May 22, 2022
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That's interesting, it could suggest there is a driver problem. Can you go to safe mode again (without uninstalling driver) and see if both are seen?
Just checked and nope, just the bottom one is detected
Edit: saw that there was a "Show hidden devices" option and enabled it. Both show up now, but the top one is greyed-out. It's also got this Code: 45 thing in the properties.
https://1drv.ms/u/s!AnMexrHfXjlfhdNdkEglAxseOn8-5g
 
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DRagor

Illustrious
Yeah, show hidden devices shows those that are currently not connected. For example if you were to connect one monitor with 3 different cables to PC you would get it 3 times in Device Manager as different devices. Then when you disconnect 2 cables you will see two of them move to hidden devices with the same 45 code. So this means for some reason your motherboard detects only one Titan at a time. I don't see any BIOS setting that could affect it.
 
May 22, 2022
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Yeah, show hidden devices shows those that are currently not connected. For example if you were to connect one monitor with 3 different cables to PC you would get it 3 times in Device Manager as different devices. Then when you disconnect 2 cables you will see two of them move to hidden devices with the same 45 code. So this means for some reason your motherboard detects only one Titan at a time. I don't see any BIOS setting that could affect it.
Ohh ok, gotchu.
But yeah it's still not detected... I even changed the SLI HB bridge and nothing...
Should I run DDU again?
 

Karadjgne

Titan
Ambassador
It's an ROG Maximus, it supports SLI. All ROG boards do. It's only low end budget mobo's that do not.

What version of Windows? Win 10 originally didn't support SLI, as SLI is DX11 based and Win10 is DX12 (mgpu) based. It was later fixed, sort of.
  1. On the desktop, right-click and select NVIDIA Control Panel.
  2. On the left side of the NVIDIA Control Panel, select Configure SLI, Surround, PhysX.
  3. Under SLI Configuration, select Maximize 3D Performance, and then select Apply.
It will require a bridge for sli functionality. Check with GPU-Z, that's the only program I know of that actually finds both cards, otherwise Win10 only sees 1.

Some ppl have had luck by disabled Windows Search in services.msc (change wsearch startup type to disabled)
 
May 22, 2022
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It's an ROG Maximus, it supports SLI. All ROG boards do. It's only low end budget mobo's that do not.

What version of Windows? Win 10 originally didn't support SLI, as SLI is DX11 based and Win10 is DX12 (mgpu) based. It was later fixed, sort of.
  1. On the desktop, right-click and select NVIDIA Control Panel.
  2. On the left side of the NVIDIA Control Panel, select Configure SLI, Surround, PhysX.
  3. Under SLI Configuration, select Maximize 3D Performance, and then select Apply.
It will require a bridge for sli functionality. Check with GPU-Z, that's the only program I know of that actually finds both cards, otherwise Win10 only sees 1.

Some ppl have had luck by disabled Windows Search in services.msc (change wsearch startup type to disabled)
  1. It's Win 10 21H2 19044.1706
  2. That option doesn't even appear in the NV Control Panel. Both Surround and PhysX are there, though.
  3. I've tried with two SLI HB bridges and with both the PC still fails to detect both GPUs, only DDU detects both, not even GPU-Z.
 
May 22, 2022
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Certainly you can try different nvidia driver version. Also have you tried without SLI bridge?
I'm currently trying with 456.71. No luck.
Same issue without the SLI bridge (but with no SLI bridge it detects the first GPU, and runs at x8 Native).
 
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May 22, 2022
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Updated to 512.77 (with direct download from Nvidia's site, clean install of everything except GFE) and reapplied the EVGA SLI HB bridge.
Now only the top card is detected on x8 speed even though the bottom has power and has its fan running. Not detected in anything (BIOS, GPU-Z, etc.) except for DDU.
 
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