I have asus laptop with AMD Radeon 780M IGPU + NVIDIA GeForce RTX 4060 Mobile MAX-Q DGPU and KDE6 and Wayland session.
Laptop monitor connected to AMD GPU, external monitor connected to nvidia GPU (HDMI port).
When I run glxgears benchmark test in kde 6 wayland session on 555.42.02 nvidia-open driver or 555.42.02 nvidia proprietary driver without nvidia.NVreg_EnableGpuFirmware=0 kernel option on my external monitor connected to nvidia hdmi port I have low fps framerate equal to half the screen refresh rate (in my case I have only ~37-38 fps when external screen refresh rate 75).
This looks like a bug 452219 – Low fps and high CPU usage on external monitor connected to NVIDIA when default GPU is Intel but it nvidia diriver regression because on nvidia-open 550.xx driver or nvidia proprietary driver 555.42 drver wih nvidia.NVreg_EnableGpuFirmware=0 kernel option I have normal framerate on extenal monitor.
I can not use nvidia proprietary driver 550.xx or 555.42 because it causes the kernel to panic Series 550 freezes laptop - #135 by mario156090 and nvidia can not fix this problem more than 3 monthes.
I do not want use nvidia open driver 550.xx because with this driver and external monitor I have very large cpu utilization for kwin_wayland proccess