XRDP Xorg vs Xvnc for 4K60 video playback – significant improvement with Xorg

[Harjinder Singh]

I've been evaluating XRDP as part of a Linux VDA comparison, using the same AlmaLinux 9.8 VDA, NVIDIA Quadro P4000 and 4K60fps HDR movie.

All my initial tests with XRDP was using the Xvnc backend (recently upgraded to TigerVNC 1.16.2). Video playback using SMplayer was noticeably less smooth and there was noticeable audio drops. SMPlayer viewport/window size is 1920 x 1080 - the display is 1440p.

I've now tested the same workload using an xorgxrdp/Xorg session. The difference is quite significant:

• Video playback is considerably smoother and much closer to ThinLinc.
• Audio playback is clean, with no audible drops.
• GPU utilisation is ~35%. (same as xVNC)
• NVDEC utilisation is ~45%. (same as xVNC)
• CPU load remains the same as XRDP/xVNC at approximately 2.5 / 1.5 / 0.9, so the improvement does not appear to be simply due to lower CPU utilisation.

The VDA and media workload are otherwise unchanged.