The tutorial page is just a subterminal showing man aerc-tutorial. You can navigate it faster with ^d, pgdown/space, and so on.

Please re-open this one.

I observe the same problem. :help inside aerc opens man page but performance of the subterminal is very slow. If I press and hold "j" to scroll down the scrolling progressively slows down with visible lags and visual artifacts

I just tried out aerc for the first time and scrolling through a mails with patches was a bit disappointing. When skipping through content via PageUp/PageDown the redraw rates felt very slow/sluggish. Adding -c to the less invocation reduced the visual effects but it still feels very slow compared to just scrolling through dmesg | less (or similar).

I think this might be a really bug worth tracking. Maybe the topic is wrong since it seems like a more generic problem.

I've done a bit of experimentation on this and it seems that the more cells there are in the embedded terminal, the slower it redraws. This seems like it's probably an issue in the upstream emulator library rather than aerc, though I can't say for certain.