The only thing I've been able to do is put the game in Win98/Me compatibility mode (that seems to slow down game play to normal frame rates with the exception of only the main menu), as well as set the programs core affinity to only 1 core in task manager (which frankly doesn't seem to make a difference). I also disabled visual themes and desktop composition, but they seem to have made negligible improvements.

Are you running Win XP? This was a well-known old problem, happens because your CPU is so much faster than what the game was designed for. Try using a throttling tool, like CPU grabber. Also, contact GOG support. I thought they'd somehow resolved this one.

Thank you so much. That did the trick.

Here's the even-better part: you can under-throttle your CPU to make the game run a little faster and make it more exciting ;)

Awesome! I'll give that a try.

No need to download a tool if you want. Just Cntrl-Alt-Del to the task manager. Find the game in the list. Right click game, select Go to process. Right click process, Set Affinity. (Depending on CPU numbers might vary) Select CPU 0 to use only one CPU for the game. Same trick works for Painkiller which would run at light speed unless toned down CPU wise.

Have fun!

It's not a matter of multi-threading, but a matter of clock frequency. Any single core nowadays is several times faster than the standard that Rogue Squadron was designed for. Recent Windows versions seem to emulate this better, but XP doesn't.