Performance issues with kde plasma

I got a few issues when using kde plasma on qubes 4.3
So when i drag windows across my screen my fps drops to 15 this is only with virtual machines so not with like windows that are from kde or qubes itself

Also when i full screen or make the windows bigger from a youtube video the fps is also very low like its unwatchable even when i give the qube like 10 vcpus and 8 gb ram

You dont say what system you are using or provide any relevant details.
On basic x230 machines videos are viewable fine (fps may be low but
watching is fine.) Depending on your system, 10vcpus and 8Gb RAM is
unlikely to help.