Gtk3 literally uses the exact same rendering API as Gtk2, Cairo, which is accelerated by your Xorg driver the same as it has been for decades. None of this eve

Gtk3 literally uses the exact same rendering API as Gtk2, Cairo, which is accelerated by your Xorg driver the same as it has been for decades. None of this even matters because Firefox isn't a traditional application and renders most thing itself using Skia.