So far as a "fast disk" bug is concerned, there's a simple way to test if its at 133 or above - just get someone who's CPU can't handle above 133 to run it for a few moments... I might try it (I know mine handls it at 320x200, but not the full screen. At least not for anything more than 10 mins).
Also, interestingly, this sounds very similar to a bug I experienced using an adventure game on my PC - the Companions of Xanth game - whereby I ran it, and it went fine, but once I quit, windows was running at least 5x its normal speed. In every way - program loading and sound playing. Since my computer didn't die from overheating (and I'd have expected it to if it was being overclocked), I used it to speed up things like web surfing, flash movies (without sound only), and newer games. Bizarre bug, but 'twas very useful. If we've run into the same thing here and its recreatable, think of the possible benefits lol. Smash into it as a routine at the start of, say, a SNES emu and you get some bizarre speed increase that's completely unexplainable.
Of course, it could be simply that more of the CPU was being directed towards the task at hand (i.e. browsing the web), which seems more likely than a sudden jump in performance with no consequences... anyone more experienced than I in these things, ever heard of anything similar?
Happened several times, btw, but not all the time... try it out with Xanth and see what happenns lol.