Comment by somat | Hacker News Reader

Comment by somat | Hacker News Reader

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The turbo button was always on, or it should be. you would turn it off to downgrade your pc to run at the speed of the original IBM PC in the mostly vain hope that whatever old game that was programmed for that exact speed would start to run right. It was slightly be fore my time(we had a 286 with the button, but I was to young to be curious about it) Would the pc take the speed change without problems or was it best to reboot? I sort of hate whatever marketing genius figured out to label it "Turbo" instead of "Slow" But they definitely earned their bonus.

The real weird one from that era was the 7 segment led MHz displays that were popular in the 386/486 era. It was weird because the the chips could not change speed in the first place. And I don't want to say every system was like this, but every one I ever saw was set by a set of static jumpers or a dip switch. When you upgraded your cpu you put the little sticker that came with it on the chassis and changed the jumpers, they served the same purpose.

The way I remember the turbo button it just halved the clock speed when not depressed, but it didn't bring it back to the original IBM PC's speed.

I do remember using it to make older games play less bad, but, as you say, this rarely worked, I think precisely because the speed was never the original one (I don't remember the clock speed of my first PC, but the first one with a turbo button ran at 33 MHz which I'm sure is a lot more than twice the speed of the first one; seems closer to 8x from what a quick search implies).

It was more than half (depending on age). I thought it always took you to 4.77 MHz to match the original 5150.

I didn't know, thanks, you've sent me down a small rabbit hole reading up on this!

Sure. I never understood it as a kid. The fact it slowed your computer always confused me since I didn’t realize it was on by default.

I didn’t learn the real purpose until long after they were gone.

Yes, our first family PC was a 386 that we could slow down from 33 to 16 MHz with the Turbo button. It even had the segment display to show the current clock rate.

I knew what it was for and had some old games that ran too fast, but from what I remember, in most cases 16 MHz was still much too fast, so I didn't use the button much.

I think it was no problem to switch Turbo mode on and off in the middle of running software.

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