Your system information
-
Steam client version: 1784778118
-
SteamOS version: 3.8.16
-
Opted into Steam client beta?: [Yes/No] No
-
Opted into SteamOS beta?: [Yes/No] No
-
Have you checked for updates in Settings > System?: [Yes/No] Yes
-
Intel i9 10900k
-
AMD RX 6900 XT (Reference)
-
128GB DDR4
-
z590 MSI motherboard
-
Dell Alienware AW3225QF 4k/240hz monitor
Please describe your issue in as much detail as possible:
When running SteamOS on a desktop PC with an AMD Radeon RX 6900 XT connected to a Dell Alienware AW3225QF, the display exhibits a subtle whole-screen brightness fluctuation whenever the screen contents are changing (desktop window movement, games, etc.).
At the same time, the monitor's OSD reports the refresh rate momentarily dropping below the configured refresh rate (for example, from 120 Hz to approximately 107 Hz) before immediately returning to 120 Hz. It happens rapidly and often. It is present in SteamOS, as well as the SteamOS live USB installer.
It only happens at specific resolutions, and occurs over HDMI or DisplayPort - 4k/120hz specifically is where I'm trying to use the monitor. I have to use HDMI for streaming capture, though I eliminated the capture card as the source of the issue. 1080p/240hz and 1080p/120hz also exhibit the issue, though 1440p/120hz does not. 4k/240hz works fine over DP, though that is not available over HDMI. 1440p/120, 4k/60, 1080p/60 all work fine.
The issue only occurs on SteamOS.
The same hardware is stable under Windows, Fedora KDE Live, and Bazzite. The monitor also behaves normally with a Mac mini M4 Pro.
Bazzite nor Fedora present the option to enable or disable VRR on this display, so I'm wondering if's a bug in SteamOS's implementation of VRR. If I enable VRR in SteamOS, the frequency of the monitor fluctuates between 120hz, 107hz, and 48hz. I leave it disabled Adaptive refresh due to the gamma-shift/brightness flicker of OLED screens at low brightness levels, which is how I noticed it was doing this 120-107hz flicker.
My Steam Deck, when connected to the same display, does not display this kind of flickering as well - however it does not have 4k/120hz as an option so I cannot test that resolution and refresh rate. 1080p/120 or 240 does also work fine, however.
Expected behavior
When configured for a fixed refresh rate (for example 3840×2160 @120 Hz), the display should remain visually stable and the monitor OSD should continue to report a constant 120 Hz while desktop content changes.
Actual behavior
Whenever screen contents are changing:
- moving desktop windows
- desktop animations
- games, especially in menus
The monitor exhibits a subtle whole-screen brightness fluctuation.
At the same time, the monitor OSD briefly reports refresh rates below the configured refresh (commonly around 107 Hz) before returning to 120 Hz.
When the image is static:
brightness is stable
OSD remains at 120 Hz
Reproduction
Boot SteamOS.
Set the display to 3840×2160 @120 Hz.
Open Desktop Mode (also reproduces in Gaming Mode).
Drag windows around the desktop or run a game, navigate through menus.
Observe:
subtle whole-screen brightness fluctuation
monitor OSD briefly reporting approximately 107 Hz instead of remaining fixed at 120 Hz.
Additional Information
- Reproduces over both HDMI and DisplayPort.
- VRR is disabled.
- 10-Bit color is selected in KDE display configurator, although the monitor OSD shows 24-bit, as though SteamOS is really only pushing 8-bit (Windows and MacOS both show pushing 30-bit according to the monitor OSD)
- modetest reports identical connector modes and connector properties between SteamOS and Fedora.
- The issue occurs on both an installed SteamOS system and the official SteamOS installer Live USB.
- Fedora KDE Live and Bazzite do not reproduce the issue on the same hardware.
- Windows and macOS also produce stable output on the same hardware.
Because Fedora and Bazzite do not reproduce the issue despite using the same GPU, monitor, and DRM display modes, this appears to be specific to SteamOS rather than a general AMDGPU, Wayland, or monitor compatibility issue.
Attachments
modetest -c output (SteamOS)
modetest -c output (Fedora)
glxinfo -B
vulkaninfo --summary
Video clip showing monitor reporting frequency fluctuations.
Fedora glxinfo vulkaninfo.txt
Fedora modetest output.txt
SteamOS glxinfo vulkaninfo.txt
SteamOS modetest output.txt
Frequency Flicker
Your system information
Steam client version: 1784778118
SteamOS version: 3.8.16
Opted into Steam client beta?: [Yes/No] No
Opted into SteamOS beta?: [Yes/No] No
Have you checked for updates in Settings > System?: [Yes/No] Yes
Intel i9 10900k
AMD RX 6900 XT (Reference)
128GB DDR4
z590 MSI motherboard
Dell Alienware AW3225QF 4k/240hz monitor
Please describe your issue in as much detail as possible:
When running SteamOS on a desktop PC with an AMD Radeon RX 6900 XT connected to a Dell Alienware AW3225QF, the display exhibits a subtle whole-screen brightness fluctuation whenever the screen contents are changing (desktop window movement, games, etc.).
At the same time, the monitor's OSD reports the refresh rate momentarily dropping below the configured refresh rate (for example, from 120 Hz to approximately 107 Hz) before immediately returning to 120 Hz. It happens rapidly and often. It is present in SteamOS, as well as the SteamOS live USB installer.
It only happens at specific resolutions, and occurs over HDMI or DisplayPort - 4k/120hz specifically is where I'm trying to use the monitor. I have to use HDMI for streaming capture, though I eliminated the capture card as the source of the issue. 1080p/240hz and 1080p/120hz also exhibit the issue, though 1440p/120hz does not. 4k/240hz works fine over DP, though that is not available over HDMI. 1440p/120, 4k/60, 1080p/60 all work fine.
The issue only occurs on SteamOS.
The same hardware is stable under Windows, Fedora KDE Live, and Bazzite. The monitor also behaves normally with a Mac mini M4 Pro.
Bazzite nor Fedora present the option to enable or disable VRR on this display, so I'm wondering if's a bug in SteamOS's implementation of VRR. If I enable VRR in SteamOS, the frequency of the monitor fluctuates between 120hz, 107hz, and 48hz. I leave it disabled Adaptive refresh due to the gamma-shift/brightness flicker of OLED screens at low brightness levels, which is how I noticed it was doing this 120-107hz flicker.
My Steam Deck, when connected to the same display, does not display this kind of flickering as well - however it does not have 4k/120hz as an option so I cannot test that resolution and refresh rate. 1080p/120 or 240 does also work fine, however.
Expected behavior
When configured for a fixed refresh rate (for example 3840×2160 @120 Hz), the display should remain visually stable and the monitor OSD should continue to report a constant 120 Hz while desktop content changes.
Actual behavior
Whenever screen contents are changing:
The monitor exhibits a subtle whole-screen brightness fluctuation.
At the same time, the monitor OSD briefly reports refresh rates below the configured refresh (commonly around 107 Hz) before returning to 120 Hz.
When the image is static:
brightness is stable
OSD remains at 120 Hz
Reproduction
Boot SteamOS.
Set the display to 3840×2160 @120 Hz.
Open Desktop Mode (also reproduces in Gaming Mode).
Drag windows around the desktop or run a game, navigate through menus.
Observe:
subtle whole-screen brightness fluctuation
monitor OSD briefly reporting approximately 107 Hz instead of remaining fixed at 120 Hz.
Additional Information
Because Fedora and Bazzite do not reproduce the issue despite using the same GPU, monitor, and DRM display modes, this appears to be specific to SteamOS rather than a general AMDGPU, Wayland, or monitor compatibility issue.
Attachments
modetest -c output (SteamOS)
modetest -c output (Fedora)
glxinfo -B
vulkaninfo --summary
Video clip showing monitor reporting frequency fluctuations.
Fedora glxinfo vulkaninfo.txt
Fedora modetest output.txt
SteamOS glxinfo vulkaninfo.txt
SteamOS modetest output.txt
Frequency Flicker