Jumpers what a luxury.
The old Kit used Oscillator blocks.
Basically a crystal and Oscillator circuit in a metal can.
If you were lucky they were socketed, if not then it was soldering iron time.
Used to make adapters out of veroboard 4 pins on the bottom to solder into the motherboard and 2 sockets on top.
One for the square oscillators and one for the oblong ones, they came in 2 sizes.
Overclocking is not new.
It's just that every one can do it these days.
Zero skill is required to alter a few numbers in the bios.