It is absolutely possible, I've seen multiple such systems. > In fact, you can't guarantee 5us for anything, at least not on common operating systems. Oh yes

It is absolutely possible, I've seen multiple such systems. > In fact, you can't guarantee 5us for anything, at least not on common operating systems. Oh yes you can, with a screen-sized kernel cmdline, some proper configuration, both hardware and software, and a bit of luck.