Interesting bit of trivia: the MHz LED display on the front of most PC cases was typically configured by jumpers and wired directly to the turbo button; it did not read the actual speed from the motherboard. So if you wanted, you could make it say "HI" for high speed and "LO" for low speed.
Yep, I remember spending an afternoon reverse-engineering the jumper configuration to change the numbers to match the CPU I had just upgraded. I may still have the diagram I drew somewhere. And I thought I didn't have enough free time back then.
