It's pretty amazing how well Intel has achieved that goal. Modern Intel CPUs can still natively run MS-DOS and applications for it. There are obviously problems

It's pretty amazing how well Intel has achieved that goal. Modern Intel CPUs can still natively run MS-DOS and applications for it. There are obviously problems with some games running too fast, and I seem to remember some issue in a common runtime (Turbo Pascal?) where a timing calibration loop would divide by zero because it took zero timer ticks to run a busywait loop. Those were already issues 20+ years ago, though.