[Portal] Performance issues near fire effects [Windows, Nvidia, DXVK 2.7.1, d3d9]
Thank you for the well made issue.
Are you sure this doesn't happen in native dx9?
At least from some of my own testing i seem to get the same frame time spikes with and without dxvk on Windows.
It looks a lot worse with the dxvk frame time graph than a lot others because of how it autoscales and zooms in. So for testing on Windows i used FPS Monitor instead of MSi Afterburner/RTSS so i could scale the graph.
I am capping the fps to 60 via the ingame cap. Testing is done with a RTX 4080
FPS Monitor and dxvk hud
Scaling in fps monitor is set to min 13 and max 21
Native dx9
dxvk master
For comparison this is how it is presented in MSi Afterburner/RTSS
MSi Afterburner/RTSS
Native dx9
dxvk master
You are absolutely correct. The FPS Monitor is much more precise than RTSS and shows frame time spikes in dx9 mode as well. The choppy performance however is only present with DXVK installed and the game is smooth in dx9 mode despite what frametime graph shows.
THAT SAID another case is solved.
I am capping the fps to 60 via the ingame cap.
Capping framerate with the ingame cap solved the problem. I was capping it with Nvidia Control Panel, and for whatever reason, it was working flawlessly until reaching that particular room. With Nvidia framerate cap enabled fire effects cause heavy stutters.
If wanted then dxvk also provides its own frame limiter via either the DXVK_FRAME_RATE env var or dxgi.maxFrameRate & d3d9.maxFrameRate via the config file. The former takes precedence.
Looks like capping fps with d3d9.maxFrameRate also works properly. Only Nvidia Control Panel fps cap causes performance issues for DXVK.
Launch options
DXVK_FRAME_RATEx1 2025-11
When I get to the fire room in Portal I get weird performance issues: https://youtu.be/wQSu5fyq1qk
As you can see from the video, the framerate stays pretty consistent (as is the case for the rest of the game), but frametimes fluctuate wildly which causes choppy/jittery animation. The same doesn't happen in DirectX 9 mode.
Software information
The settings applied can be seen in the video.
System information
Apitrace file(s)
Log files
hl2_d3d9.log