I tend to watch lectures at 2x or 1.75x speed, and I tone it down for more difficult stuff, or pause, or rewatch. I think at 2x it's pretty even with how fast I can read, maybe even a bit faster. Modulating it isn't perfect but it's workable. Also, I struggle very hard to pay attention to almost any lecturer, my mind drifts very quickly and takes a while before I realize it's drifted. But at 2x I find my ADD is mostly defeated.