Bad YouTube/Video/Games performance, but good performance otherwise - Windows 10 VM w/ GPU passthru

[iAdjunct]

My host is an EVGA FTW-K X299 + i7-7820X with a Radeon 580 RX in the primary x16 slot and a Nvidia GTX 1080 Ti in the secondary x8 (CPU, not PCH) slot running unRAID 6.8.2.

 

My client is Windows 10 Enterprise with the Nvidia card passed through (both audio and video) and 4 [real] cores passed through. The VM's configuration is attached, though apparently Windows tacked on a .txt extension...

 

The computer runs fine. I'm running 4k@60Hz to a Samsung TV, and everything is responsive. There are no color/pixel aberrations, no choppiness, etc; when I move the mouse around, move windows around, type, scroll in the web, everything works wonderfully.

 

I ran the benchmark from userbenchmark and got slightly slower RAM performance but nearly identical 4-core CPU performance and GPU performance as this same computer gets bare-metal (but with the 1080 Ti in the primary x16 slot). Clearly something is working right (though, interestingly, this computer seems to generally be slower than expected - the GPU isn't performing as well as this card is expected to, but the key is that it's the same as the bare-metal computer, and I played Borderlands 3 at 4k on very high settings with only minor degredation, let alone streaming a video).

 

If I open a game... Like Portal 2 (let alone Borderlands 3)... or if I play a video on YouTube, I get horribly choppy video (probably 2 fps) and stuttery/choppy audio. This happens whether it's full-screen or a small window, and happens to all audio, and it doesn't matter if it's in Chrome or a video from a local network server played with Windows media player, or if it's a system alert sound, whether it's HD or SD, etc - they're all... slow. Here's a good video shot at a bad angle of the behavior.

 

Why is this an issue? I have no idea what is causing this and why it's so limited to video playbacks.

VMConfig.xml.txt

Edited March 5, 2020 by iAdjunct

[JonathanM]

Have you applied the MSI fix?

[iAdjunct]

1 hour ago, jonathanm said:

Have you applied the MSI fix?

I have not. I did not know there was such a thing.

 

I just found that here. However, that section says it tells me how to do it, then proceeds to tell me how to check if... MSI is... used? It doesn't actually tell me if I need to perform the "fix" or how to fix it.

 

For reference, my `lspci` is showing this for the 1080 card:

 

Capabilities: [68] MSI: Enable+ Count=1/1 Maskable- 64bit+

 

So, if enabled and used is what's it's supposed to be, then I don't need the MSI fix.

Edited March 5, 2020 by iAdjunct

[testdasi]

Watch SpaceInvader One vid. The link to the msi fix is in the vid description.

 

 Tha

[civic95man]

16 hours ago, iAdjunct said:

Capabilities: [68] MSI: Enable+ 

I believe that means that MSI is enabled for that device in the guest OS.  If I remember right, I had to run some utility in the VM (windows 10 in my case), which enabled the MSI on a per device basis - I was having issues with sound.  I can't remember what the utility was called but it also showed what was/was not enabled yet.

 

In my case, I built my VM with Q35 rather than i440fx and haven't had any issues since.  Maybe check to see what the PCI lane width is but even at 1x, I would expect more than 2FPS.

 

Good luck

Edited March 5, 2020 by civic95man

[iAdjunct]

Enabling MSI for the audio card worked - thanks everybody!

 

It wasn't clear from the wiki that this had to be done for both the GPU (which was done automatically) and the HDMI sound output device too.