How much does this speed up sessions over higher latency connections I wonder? I have been looking for RDP performance similar to that of Windows on Linux, but up until now it has been semi slow over WANs.
Very well. Assuming you have identical CPUs (say Intel with QuickSync) The performance constrains are really more dependent the desktop environment you choose (I have good results with GNOME on a LAN but LXDE works better in Azure since it has less decoration).
CPU overhead is minimal if you use xorgxrdp-glamor on an Intel iGPU. If you don’t use glamor or don’t have an iGPU then you get llvmpipe rendering for graphics and CPU H.264 encoding for the RDP stream (but RDP will seldom negotiate H.264 in that scenario)