The "Turbo" button was very common in 286 and 386 PC clones, less common in 486 PCs, and almost extinct by the time Pentium processors became mainstream in the late 1990s.

I’ve never had a personal computer with a Turbo button. Not my.KIM-1, not my OSI Superboard II (though I added a jumper and boosted it to 2MHz), not my Radio Shack Color Computers, not my Macs ...

To patch the issue temporarily, some computers in the early 90s included a “TURBO” button which actually slowed the computer’s clock speed down in order to help older software run without ...