I had a Turbo button on a 80386, I believe it brought it down from 25 MHz to 12 MHz. I think they were still common on 486s too though, it wasn't until Pentiums

I had a Turbo button on a 80386, I believe it brought it down from 25 MHz to 12 MHz. I think they were still common on 486s too though, it wasn't until Pentiums that the option stopped being included.