[javagram]

Isn’t it possible to disable gpu in about:config?

[ncmncm]

about:config certainly has lots of settings to turn off, but I manifestly have not found enough of them, if indeed any number is enough.

[the8472]

You can cross-check about:config with the about:support Graphics section.

A few switches of relevance: layers.acceleration, webgl.disabled, media.hardware-video-decoding.enabled, gfx.webrender.force-disabled

[ncmncm]

Aha! gfx.webrender.force-disabled was false. Now to ser how much difference it makes.