The majority of the slowdown on larger canvases with ArtRage comes from the calculation of the interaction of paint volumes / wetness / colour rather than the process of getting it to the screen. We've looked in to potentially using GPU acceleration in the past but those calculations aren't really appropriate for that model. Apps that only work with colour can generally take advantage of GPU acceleration, but when you're dealing with the kind of calculations our media simulation does it's not necessarily as straightforward and basically wouldn't help.

Interface lag or stutter is unusual though, that's not something I've seen with large canvases outside of potential slowdowns in layer thumbnails updating or paint previews updating, both of which are dependent on the kind of calculation I mentioned above.