[ndiddy]

This isn't really true beyond basic Windows GUI only programs. For example, most 2D Windows games made before the mid-2000s used a rendering API called DirectDraw. On Windows 8 and newer, DirectDraw goes through some sort of fallback rendering path and these games won't run at more than around 30 FPS with bad frame timing. The same thing happened with games that used 8-bit color with hardware palettes. Windows 8 and newer will only run at 32-bit color (the "run with 256 colors" compatibility setting was changed to just put a low color filter over the system graphics), so they are broken as well.

[int_19h]

DirectDraw is an incredibly simple API (it doesn't even have 2D primitives - just blitting rectangles of pixels from one surface to another). AFAIK the fallback is basically doing that in software - since this is plenty fast these days - and letting the compositor handle the actual screen update. There's no reason why this would result in 30 FPS even on 20-year-old hardware, and indeed I regularly play a DirectDraw game from 1999 on Win11 without such issues.