Never type this stuff into your computer

[InbetweenDreams]

In my case Cinnamon's performance declined over time, rebooting "fixed" it until it slowed down again, didn't reflect in an increase in system load and 3D acceleration wasn't affected. It's been a couple years so maybe the problem was fixed?

As far as this screenshot about a bug in KDE... First I'm sure there's bugs in GNOME, Cinnamon, XFCE or whatever, just as there are likely bugs in the kernel, some driver or whatever. Not sure what the full backstory is on this and frankly I could care less. I like what I like and that's that. If you like Cinnamon and Arch Linux, that's great, use what you like.