I think with older hardware you have to be quite careful about how stuff is drawn to the screen. For example if the distro comes with a display compositor enabled by default, you might want to disable it or see if there is a faster alternative. You might want to avoid watching videos in the browser where it has to composit the video with everything else on the page in a relatively inefficient manner, and instead stick to watching videos with something like mpv where it can draw straight to the screen, and make sure to configure it with whichever video output seems to be fastest on your hardware, etc etc.