Yeah it's LLVMpipe, it's basically doing everything in software and Plasma uses quite a bit OpenGL for animations and compositing. A lighter WM like Fluxbox could maybe be easier on the CPU. In any case, looking back at Nouveau, writing decent drivers for a GPU nobody has specs of is definitely challenging. Only time can tell.

Working off inprecise documentation or reverse engineering everything is nothing new in the Linux world. At least on the M1 drivers seem to be able to exert full control over the card, compared to newer Nvidia cards where firmware signed by Nvidia is required to boost the card to a reasonable clock frequency!

I'll bet that's thanks to the mining market buying cheap cards and overclocking them into the ground. Very annoying for the wider market, certainly...

The % usage is not indicative of anything considering it will use as much CPU as possible to reach as high a frame rate as possible

I think by default glxgears has vsync enabled. But it's trivially possible to disable it with an env var. Considering the CPU usage I assume that is what was done. 60% CPU usage for running glxgears at 120Hz seems excessive.

There is no vsync with the dumb framebuffer backend I'm using. We have a real display driver, but it needs rebasing and adapting to work on these laptops (it was developed on the Mac Mini).

I always remember glxgears running at hundreds of FPS and it being used as a poor man’s benchmark. Perhaps this has changed of late though…

I always have had to set `vblank_mode=0` to get it to run as fast as possible.

He also mentions: "buttery smooth software only rendering"

If networking and KVM suport exist for this (I think it does), then these would make great servers as well.