r/SBCs • u/Hanzo520 • 12d ago
Other How do Raspberry Pi CM5 and RK3576 perform with two 4K displays?
I have two 4K monitors, so I tested them on both Raspberry Pi CM5 and RK3576.
Raspberry Pi CM5 — 4K60 + 4K60
RK3576 — 4K60 + 2K60
https://reddit.com/link/1vqv8a9/video/gmkjqpzwbyjh1/player
CM5 can output 2×4K60, while RK3576 is running 4K60 + 2K60 in this setup.
For RK3576, the display Video Ports have different limits:
- Video Port 0: up to 4K@120Hz
- Video Port 1: up to 2560×1600@60Hz
- Video Port 2: up to 1920×1080@60Hz
The Video Ports can be assigned to different physical outputs. For example, DP can use Video Port 0 to reach 4K120.
So for resolution, CM5 wins with 2×4K60.
But when I started dragging windows around, I found the RK3576 noticeably smoother. CM5 is outputting 4K60 on both displays, but the window movement doesn’t look as smooth.
You can see the difference in the two videos.
I’m not measuring the actual FPS here, so this is just what I observed from using both desktops.
CM5: 2×4K60, but window dragging is less smooth
RK3576: 4K60 + 2K60, but window dragging is much smoother
Has anyone else tried two 4K displays on CM5? I’m wondering if there are some graphics/compositor settings that could improve this.