Tertz wrote on 2016-01-28, 09:06:
World Circuit - has not fps, but other performance numbers.
More information for those interested:
This game, which is also known as Microprose Formula 1 Grand Prix, and its successor Grand Prix 2 both require you to select the frame rate you want - between 8.1 and 25.0 for the former, 8.0 and 25.6 for GP2 - then when you hold down the letter "o" key, it shows e.g. "Processor Occupancy 66%" (the value updates while you keep holding down the key). At least in GP2 (I didn't check the first version), it shows you an estimate of the frame rate you might get given your selected detail level.
I'm fairly sure that what happens is the game loop draws a frame and then if there is time free before the next frame it sleeps to slow the game down to real time, so this is what processor occupancy levels mean:
50%: The game is running at your selected FPS with plenty of margin for more things to come into view, or for you to use external views.
100%: The game is running at your selected FPS, but probably if some more objects come into view the occupancy will go over 100% and things will slow down.
200%: The game is running at half your selected FPS, but game time is also running at half of real time, so you are getting your selected number of frames per game second. It makes the game easier to play because you have more time to react 🤣
So while it doesn't show FPS, you can - as Tertz said - get similar performance numbers from it, and even I suppose use some math to figure out what the FPS would probably be.
Incidentally GP2 is a game I have paid a lot of attention to the performance of, because to run it at maximum detail in SVGA resolution on the Monte Carlo track without it exceeding 100% CPU usage requires an unreasonably powerful computer for a DOS game. This game came out in 1996, but on my Athlon XP 2400 system it still sometimes reaches 50% CPU usage when running under DOS. I can't run it with that detail level under DOSbox on my fastest PC, and it runs in VirtualBox but the simulation speeds up and slows down, presumably because it's expecting dedicated use of the CPU rather than to be run under an operating system which is only scheduling it every now and then. If it wasn't written to try to run at a fixed FPS it might deal better with that!