Turbo Button on old PC?

[Safeway]

This classic may have been bleeding-edge one day ... a long, long time ago. It's LED reads 166 mhz. The turbo button is active. What's it do?

 

[high]

prehistoric overclock

 

[bluemax]

Originally posted by: high
prehistoric overclock

Nope. Turbo meant the machine was running at FULL normal speed - as opposed to non-turbo which would be about half of full/normal speed.

No overclocking. 33MHz was 33MHz, not 40.

 

[high]

ya i know

 

[So]

more like prehistoric underclock

bluemax has it pretty much right... lemme get a link...

 

[So]

best info I could fin (not very good IMO)

http://www.pcguide.com/ref/case/switchTurbo-c.html

 

[StrangerGuy]

Those were in the good ol' days.

 

[Delorian]

I miss my 386sx 25 w/turbo button. They need an A64 turbo button!

 

[Rotax]

the turbo button underclocked like most folks said...and in TURBO mode it was normal speed

the reason for this was mainly some DOS apps needed to be *underclocked* to run correctly, or in games for example, things would run all over the screen WAY too fast...

like playing pac-man where he'd run around the scree 2x as fast (for example)


thats how i understood the turbo button at least...

 

[So]

Originally posted by: Rotax
the turbo button underclocked like most folks said...and in TURBO mode it was normal speed

the reason for this was mainly some DOS apps needed to be *underclocked* to run correctly, or in games for example, things would run all over the screen WAY too fast...

like playing pac-man where he'd run around the scree 2x as fast (for example)


thats how i understood the turbo button at least...

I still remember the day when one of my friends got a new Pentium 100 cpu and his computer had a turbo button. The thing had a two digit Mhz LED readout, and when he pressed the turbo button it went from reading 33 to 99 my friend looked at us and said, "it's really 100, but obviously there're only two digits" my other friend that was there and I just went "Wow...."

That was an awe inspiring moment. A 100Mhz computer.... :heart:

 

[ROcHE]

I had a 8086 with default 4.77mhz and turbo 8mhz. Screaming machine.

 

[Vortex22]

I remember my old 386. It went from 8 to 16 with that button...SPEEEEDDDD!!!

 

[bluemax]

Originally posted by: So

Originally posted by: Rotax
thats how i understood the turbo button at least...

I still remember the day when one of my friends got a new Pentium 100 cpu and his computer had a turbo button. The thing had a two digit Mhz LED readout, and when he pressed the turbo button it went from reading 33 to 99 my friend looked at us and said, "it's really 100, but obviously there're only two digits" my other friend that was there and I just went "Wow...."
That was an awe inspiring moment. A 100Mhz computer.... :heart:

I still remember the near shock when I found someone who did a home-mod back in the XT/286 days. Took a rotary dial and was actually able to click it up and down 1MHz per tick! And the LED readout would show it! 1-20MHz I think it was (making it a 286)...
Man... I remember how big the archetecture jumps were from XT to 286 to 386! Night and day difference! It really slowed down after that.......

 

[So]

Wow...that's quite the hack! The only time I've seen anything like that is with the lab single board computers, which had HP frequency generators creating their clock. I never tried to overclock those tho' it'd have screwed with our serial connection, which was the system's only IO port.

 

[wetcat007]

Some really old applications needed a set CPU speed, otherwise they would run too fast at a high clock speed, and not work correctly, so they created a button to go back to a slow speed so they would work correctly.

 

[bluemax]

Originally posted by: wetcat007
Some really old applications needed a set CPU speed, otherwise they would run too fast at a high clock speed, and not work correctly, so they created a button to go back to a slow speed so they would work correctly.

Except it would only throttle the CPU back so far... usually ~50%. 33MHz became 16. 25MHz became 12 and so on.

With the exception of the XT days which is where it originated. The Turbo switch "OFF" would yield the original IBM PC's 4.77MHz. On would be full tilt... 8-12MHz.

Wow I'm old... I still remember the sales pitch for my old Tandy 1000SX - "50% faster than the IBM PC!"
7.14MHz

And to think - that used to be GOOD!

 

[VirtualLarry]

Originally posted by: bluemax

Originally posted by: wetcat007
Some really old applications needed a set CPU speed, otherwise they would run too fast at a high clock speed, and not work correctly, so they created a button to go back to a slow speed so they would work correctly.

Except it would only throttle the CPU back so far... usually ~50%. 33MHz became 16. 25MHz became 12 and so on.

With the exception of the XT days which is where it originated. The Turbo switch "OFF" would yield the original IBM PC's 4.77MHz. On would be full tilt... 8-12MHz.

Wow I'm old... I still remember the sales pitch for my old Tandy 1000SX - "50% faster than the IBM PC!"
7.14MHz

And to think - that used to be GOOD!

I still remember my clone "Turbo-XT" system.. 7.xx Mhz of *pure power*.

Strangely enough, for apps written using floating-point math, they were still 2x as fast on that system (with 8087 co-proc), than running on an AMD 386DX-40 system without a math co-proc. That was around the time that I finally started getting serious about writing my stuff in assembly language, and after some tweaking managed to regain some respectible speeds. (Mode 13h VGA screen-scrolling with background tiles + sprites at 30fps solid, vsync enabled. Not so special nowadays, but back then that was pretty good. When I finally got my 486DX/2-66 machine, with a PCI graphics card, I could do the same at 60fps.)

Oh yeah, my clone PC-XT, had copied IBM BIOS EPROMs in it. If it couldn't boot off of the HD, it would actually boot into the IBM BASIC intepreter.

 

[Maggotry]

Anyone remember that old program called "Moslo" (more slow)? It would cripple your cpu speed through software to get old DOS apps to run correctly. Basically a software version of the Turbo button.