In my particular context, it's a Raspberry Pi on a 1920x1200 display, 1:1 pixel scaling, no antialising I know of, and... the rest shouldn't matter that much in

In my particular context, it's a Raspberry Pi on a 1920x1200 display, 1:1 pixel scaling, no antialising I know of, and... the rest shouldn't matter that much in terms of how long it takes a key pressed at the keyboard to show up in the input text area. If it does, something is quite wrong in the architecture, IMO, and it's probably 4 layers of nested libraries nobody actually understands down, buried under something else. I don't think pixel density has increased as much as you seem to think it has in the 1x scaling space. I ran some very nice 1600x1200 21" monitors back in the day - ~95 ppi. A 27", 2560x1440 monitor (my preferred native size) is 108 ppi. The 24", 1920x1200, is 94 ppi. I understand the issues with scaling a display, but those are more OS level, and shouldn't impact key-to-screen delays noticeably. It certainly doesn't on more recent Apple hardware, even if you're using some screwball non-integer scaling. But the reality remains, I now have 6GHz of CPU cores, 8GB of RAM, and things are objectively slower than 66MHz with 24MB. That's not progress.