In the case of ReMarkable 1, there are almost no issues with vectorised PDFs - when changing pages the screen update is usually the limiting factor, and that's

In the case of ReMarkable 1, there are almost no issues with vectorised PDFs - when changing pages the screen update is usually the limiting factor, and that's relatively quick. For rasters, though, it does take a while to render out (>1 second for particularly complex pages). I think this is mostly a software limitation - some time is given over to drawing and saving the small thumbnail.