How did this work?

By swapping crystal oscillators with a higher frequency.

And just yesterday, I was remembering a 6th grade science experiment that involved a radar gun that my father "borrowed" from a police dept (I suspect he paid to borrow or bought it outright and didn't tell me) and how that was somewhat sophisticated compared to the projects of other kids.

Really put me in my place with this one. Nice work.

Older CPUs didn't have a range of performance. They either worked at a clock speed, or didn't. If you put in a very high rate crystal, the CPU would either work at that higher rate without cooling, or not work without cooling. Clock speed was a constant.

>I didn’t even measure the clock speed - just wrote a little program (I think it was in QBasic) that calculated factorials or something (don’t remember the details), then measured performance difference between no cooling, ice water, and liquid nitrogen.

>My measurement technique was extremely simplistic - how much wall clock time does it take to do this computationally-intensive task. It ran faster with ice water, and even faster with the liquid nitrogen (until it died from condensation).

There is no world in which a 286 has a program that runs "slow" without cooling, and fast with cooling. If a clock speed "needs cooling", it's because the CPU crashes otherwise. If jdenning changed the crystal, THAT'S what increased the CPU speed. They seem adamant that wasn't the case though.