"Selecting this checkbox will enable the OpenGL / ANGLE canvas drawing mode. With a decent graphics card this should give faster feedback on brushes and tools. Also the canvas operations like Rotate, Zoom and Pan should be considerably faster."

I think it should be possible to do way better than that assuming the bus isn't too much of a bottleneck because you have to pull any points that are calculated back on to the CPU so that they can be drawn on the canvas and send out to the GPU again for layering.