When I noticed graphical corruption issues on Youtube and the Chicago Public Library's websites under X11 and turned accelerated compositing off at the suggestion of Michael Catanzaro, I noticed that performance of WebkitGTK+ on my laptop is much better with it turned off.
The performance problems happen under both X11 and Wayland, and are particularly nasty on Facebook, which is close to unusable, and Riot.im, which starts out okay and becomes slower as time progresses. The new layout version of Reddit doesn't work particularly well either, but the old version works okay.
With accelerated compositing disabled, sites scroll faster. Facebook, Riot, and Reddit are quite usable and don't cause my laptop to get hot and the fan to come on at 100%.
I'm using Epiphany 3.30.2 on WebkitGTK+ 2.22.5 on Fedora 29 on Intel Iris 540 (Skylake mobile) graphics.
Disabling AC degrades video playback performance though :(
Could you open about:gpu in chromium and share the gpu information here, please?
(In reply to Carlos Garcia Campos from comment #2)
> Could you open about:gpu in chromium and share the gpu information here,
Closing since we need this information to investigate. We can reopen if you provide the requested information.