Repeatable Crash Condition (multiple video cards)

**Xorn** · February 18th, 2021, 03:40

I have 5 monitors (+ occulus rift) so I handle this with 2 video cards. My GTX 1060 has two monitors plus the rift hooked up to it, and then I have a GTX 660 that the other three monitors are connected to. I tend to span my DM client across two monitors and since I started using FGU I found that it doesn't take long for the monitors attached to the GTX 660 to lock up and then immediately after my whole PC locks up. Updated my drivers right away. Then I thought maybe my old GTX 660 is finally shooting craps, but noticed it *only* happens with FGU spanning two monitors (and a different card happens to be handling each monitor). I adjusted my monitor arrangement so that the monitors I'm spanning are on the same card now, and the problem disappeared.

I'm not sure if it's even preventable--maybe a limitation of Unity or something. Anyway, making sure I'm spanning monitors connected to the same video card fixed the problem.

**Moon Wizard** · February 18th, 2021, 05:07

We don't do anything at the hardware or monitor splitting level. We just work within the abstractions given to us through the Unity game engine (i.e. how big is the window, what frame rate to use, etc.)

Since it locks up monitors and the computer, it sounds more like a driver issue when a certain type of program window spans multiple cards. It might be tied to how the Unity engine attempts to use the cards; but it's well below the level we have any control of.

Regards,
JPG

**Xorn** · February 24th, 2021, 19:38

Makes sense. I think having 5 monitors across 2 video cards is an uncommon scenario. I can state confidently that making sure the monitors you span are on the same video card resolved the lock up though.

**Tiderian Prime** · February 24th, 2021, 20:03

You might need to use SLA for a single application to work across two or more video outputs.

**Xorn** · February 24th, 2021, 20:51

SLA requires two of the same video card, right? Because the second card is just an old spare I had lying around.

**Tiderian Prime** · February 25th, 2021, 00:34

Originally Posted by Xorn

SLA requires two of the same video card, right? Because the second card is just an old spare I had lying around.

Technically you can mix. The cards need to have support for SLA. Not all cards do. But pairing different cards is usually undesirable. The better card takes a hit in performance.

**Xorn** · February 25th, 2021, 20:31

Yeah definitely not worth it in my case, my top 2 screens are just for messenger, discord, obs, and vlc (for background music).

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