Laggy external monitor with dual-gpu laptop

Issues & Assistance
1

I’ve been using CachyOS on my desktop and laptop for a while, however my external monitor on my laptop is very laggy. I’m using prime-run and env variables where I need so applications do run on my dGPU, and it’s moreso just everything that feels laggy not games specifically.

The CachyOS wiki said it was a driver issue which should be fixed, but it’s not. Beside that I can’t find any actual fixes online which are still possible. If anyone knows a solution I’d greatly appreciate it!

My system:
Operating System: CachyOS Linux

KDE Plasma Version: 6.6.5

KDE Frameworks Version: 6.26.0

Qt Version: 6.11.1

Kernel Version: 7.0.11-1-cachyos (64-bit)

Graphics Platform: Wayland

Processors: 12 × Intel® Core™ i7-10750H CPU @ 2.60GHz

Memory: 16 GiB of RAM (15,4 GiB usable)

Graphics Processor 1: Intel® UHD Graphics

Graphics Processor 2: NVIDIA GeForce GTX 1660 Ti

Manufacturer: ASUSTeK COMPUTER INC.

Product Name: ROG Strix G512LU_G512LU

System Version: 1.0

2

I’m facing similar issue on my laptop, G14 4060. When I connect external monitor using right usb port (nvidia dgpu), everything feels choppy, the animation in KDE, while if I use left usb port (amd igpu), everything is smooth again. I tested glxgears as well, and was getting 30-40 fps using nvidia dgpu, while 60 fps using amd gpu. For a temporary workaround, I have disabled my igpu from Rog control center, and everything is smooth again while using nvidia dgpu on external monitor.

3

Only thing that worked for me was selecting dGPU mode from bios.