Fixed Low FPS on NVIDIA RTX 2070 (Power Capping Issue) + Questions about DX12/DLSS on CachyOS

Issues & Assistance
1

Hi everyone,

I’ve been using CachyOS for a while now on my Alienware Area 51M laptop, which has desktop-grade components (i7 8th gen + RTX 2070), and I wanted to share what I found and ask for some help with a remaining issue.

The Power Capping Problem (SOLVED)

I started with some performance scripts to optimize fan control and game launching. Everything seemed fine at first, but I was getting terrible FPS — around 3 FPS instead of 27 FPS on Windows with the same settings.

After running some diagnostics with Claude (the AI), I discovered the GPU was power-capped at 50W instead of 115W. The fix was simple:

bash

powerprofilesctl set performance

That single command fixed it. Power limit jumped to 115W and FPS became playable again (30-40 FPS).

The System Setup

For anyone curious, here’s what I’m using:

  • Fan control script in /usr/local/bin/fan-control.sh with systemd service

  • Launch script for BLSE mod manager with Proton/NVIDIA optimizations

  • gamemode + mangohud for monitoring

  • Driver: nvidia-open-dkms (currently)

All of this works great on CachyOS.

Current Problem: DX12 and DLSS

Here’s where I’m stuck. When I enable DirectX 12 instead of DirectX 11, the game becomes unplayable again (3-10 FPS). DLSS only works with DX12, so I’m forced to use DX11 without upscaling.

On Windows, the same game runs at High/Very High with DX12 + DLSS Quality at 27 FPS without any issues.

What I’ve tried so far:

  • Proton GE-Proton10-34 (current)

  • Updated nvidia-open-dkms to latest

  • vkd3d-proton-git installed

  • Various launch options with PROTON_ENABLE_NVAPI=1, PROTON_DLSS_UPGRADE=1, etc.

None of it helped. DX12 just tanks performance.

Questions for the community:

  1. Has anyone with an NVIDIA RTX 2070 on CachyOS managed to get DX12 games running at reasonable FPS? If so, what was the fix?

  2. I’ve read that the open NVIDIA drivers might be incomplete for DLSS/DX12. Has anyone tried switching to the proprietary nvidia-dkms driver? Did it help?

  3. Is this a known limitation of the nvidia-open driver, or is there something specific to CachyOS/Proton I’m missing?

I love CachyOS and everything runs smoothly except for this DX12 issue. Any advice would be appreciated.

Thanks!

2

Using game-performance (instead of gamemoderun) in Steam launch command, or simply setting your power profile to performance via GUI (system settings or battery icon in systray) should have the same effect. Nothing wrong with doing it via that command either though.

DX12 performing poorly on Linux+Nvidia is a long-running issue: DirectX12 performance is terrible on Linux - Linux - NVIDIA Developer Forums

Expect ~20% performance drop in DX12, more in some games.

The root cause is poor interaction between vkd3d and nvidia drivers. You get similar drops in performance when using vkd3d on Windows.

It’s actively being worked on, but still incomplete / experimental last I checked.

You could try PROTON_VKD3D_HEAP=1, with recent enough vkd3d and Proton, it might help.