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**Title: RX 9070 XT – KWin Wayland Multi-Monitor Issues (4 Displays)**
Hi everyone,
I'm experiencing recurring display issues with my AMD Radeon RX 9070 XT on Arch Linux with KDE Plasma Wayland.
My setup consists of four monitors:
- **ASUS 4K:** 160 Hz (dual-mode 1080p at 320 Hz) — DisplayPort ========> ASUS ROG Strix XG27UCG-W.
- **Samsung Odyssey 49" ultrawide:** 5120×1440 at 120 Hz — DisplayPort
- **MSI 1080p:** 60 Hz — DisplayPort
- **Second 1080p:** 60 Hz — HDMI
The most common issue is a black screen at SDDM during startup in one monitor MSI ( HDMI) after loging in the monitors work correctly . However, this morning I experienced a different problem involving repeated `Unsupported screen format RA24` and `Modeset failed: Invalid argument` errors and the system was lagging badly I had to switch resolutions of the asus monitor.
Switching the refresh rate from 120 Hz to 60 Hz and back of my asus monitor temporarily resolves the display issue this morning.
Another problem is that I cannot reliably run my ASUS 4K monitor at 160 Hz. When I attempt to use that refresh rate, the entire desktop becomes extremely laggy.
I suspect this could be a display negotiation or modesetting issue involving KWin, the kernel, or the AMD graphics driver rather than a GPU performance limitation.
Has anyone experienced similar issues with a multi-monitor setup on RDNA 4? Are there any alternative workarounds or settings worth trying while waiting for an upstream fix?
Thanks in advance!
Last edited by Santo C01 (2026-10-22 01:43:34)
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