144Hz Ryzen PCI-e Passthrough

Operating Systems & Open Source Linux
1

Has anyone else had trouble running a Windows VM with passthrough on Ryzen at 144Hz? 60Hz works fine for me, but as soon as I crank up the refresh rate I get a blue screen (not a BSOD) where the screen splits in half horizontally. At first I thought it was an overclocking issue so I reset my BIOS and tried again but it still happened. Even weirder, when it automatically resets back to 60Hz after a few seconds, the bottom half of the screen flickers while the top half returns to normal. This will usually go away when I reboot the Windows VM, but sometimes it persists across VM reboots and even system reboots. I have to clear the CMOS to get the flicker to stop. Because I have to clear the CMOS sometimes I suspect it's a BIOS/motherboard issue. 144Hz passthrough worked fine on Intel, also I tried setting my monitor to 144Hz in both native Linux and Windows and it works fine so I doubt it's an issue with my monitor.

My hardware:
Monitor: Acer XF270HU
CPU: Ryzen 5 1600X
Motherboard: Gigabyte AX370 Gaming K5 (F3 BIOS, includes AGESA 1.0.0.6)
Host: Arch Linux 4.11.7 w/ GTX 960, Nvidia proprietary drivers
Guest: Windows 10 Creator's Update w/ GTX 1080, latest Nvidia drivers

Installed all the Red Hat virtio drivers, enabled MSI interrupts and did all the typical stuff for Ryzen like disabling NPT and SMEP to enable host passthrough. Everything works "fine" at 60Hz (besides the stutter and slowness from disabling NPT) but everything breaks as soon as I push further which is odd. Has anyone else tried running 144Hz with a Ryzen VM yet?

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So I guess no one else has an answer for this specific setup, but I just wanted to update anyone who might be watching this. I’m 99% sure it’s the GTX 1080’s fault. I’m not sure if this affects all GTX 1080’s, or just a 1080 mixed with Ryzen. But I suspect something is wrong with Nvidia’s drivers, or else Nvidia is doing something sneaky with Pascal. Either way i switched the 1080 and 960 around, and the 960 was capable of displaying 144Hz with no error. Switched them back and the 1080 was giving me graphical glitches again. So for whatever reason the 1080 is causing problems and the 960 isn’t. Again, I have no idea if it’s a driver issue, the brand of card or what. For anyone interested it’s a Gigabyte N1080TTOC-8GD.

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