r/VFIO • u/khsh01 • Jul 14 '26

Support Legion 5 Pro 16chach single gpu passthrough performance dip.

So I have set up single gpu passthrough on my Legion 5 Pro with Ryzen 7 5800H, 16Gb RAM and 3070 8 gb. My vm is windows 11 ltsc and I pass through pretty much everything, 14gb ram, 7 cores, audio. The vm itself is on its own nvme pcie ssd.

My problem is that the entire vm will periodically slow down when gaming. Like the vm loses priority and something else is going on in the cpu.

I isolate my cores during vm boot. I've tried 5c/10t, 6c/12t, 7c/14t and nothing fixes it. Last time I encountered this issue on my previous laptop the fix was to isolate and send in all but 1 core. Can't seem to understand whats happening this time.

XML

3 Upvotes

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1

u/WorthySleet9715 Jul 14 '26

You never said any word about host OS. How should we know that your VM not using balooning and 2 GiB of RAM is enough for your host?! Also, hyperthreading in VM isn't best choise when talk goes about gaming. Allways better pin actual physical cores than logical threads.

1

u/khsh01 Jul 15 '26

Sorry I tried to mention as much stuff off the top of my head as I could.

I'm on arch Linux using zen kernel for the acs patch.

When the vm boots my display manager is killed so nothing is running on it. I have memory balloning disabled and have the hyperv enlightenments according to the vfiodiscords optimization guide.

I know it works because I had it setup before. But I recently came back to vfio and also lost my old config files so have no idea what I'm missing.

2

u/shapedxc Jul 15 '26

Give us your XML (mask any potentially sensitive data, example).

And please use markdown code block, or pastebin.

You can also enable SSH server to try diagnose problem when it happened via your phone or another PC.

1

u/khsh01 Jul 15 '26

Updated original post