anyone know what those "turbo" buttons on the old pentium computers actually did?
Old x86 CPUs could run at two speeds. The turbo button made the CPUs run either at full clock, or 1/2 - 3/4 the rate. They were handy, especially with old games.
I've never seen a Pentium with a turbo button though. I thought they went out of vogue after the 486.
Maybe: There was a period of transition when the motherboards dropped the turbo option but the cases still had a turbo button. The switch wasn't connected to anything inside.
>>2's on the right track, but to expand for a bit, some applications (mostly games) were written to expect a processor that ran only at a certain speed (say, 8MHz). If you tried to run that program on a 33MHz processor, it would run four times as fast and be unusable/unplayable. The turbo button forced the processor to run at a slower speed for compatibility with these older programs.
Its name is a bit misleading, though; you push the turbo button to make your computer run slower…
http://en.wikipedia.org/wiki/Turbo_button has a little more info.
>>3
I saw some Socket 7 boards with headers for the Turbo switch. Giga-Byte made one. 486 boards always had headers for the Turbo switch as far as I know.
I'm trying to recall if Super 7 boards had them, but they're definitely long gone now.
A lot of old games relied on fixed-length-loops to implement delays.
e.g. a lot of BASIC programs used:
FOR i = 0 TO 1000
NEXT
That took a little while for an 8088 running at 8MHz to execute.
Unfortunately, 486s executed that in the blink of an eye, making such games unplayable.
>>5 AFAIR on 486s the switch didn't do anything, the wires were just there for compatibility. The only thing it did was to half/double the number on the front LED, number which was arbitrary anyway.
>>7 No, it did make a difference. I speak from experience.
The 486DX4 100MHz drops down to 10MHz when that button is toggled... and one does notice a significant difference.
>>8 Ah, it's possible. I really don't recall.
What I recall clearly is that the turbo button vanished about the same time the 100mhz mark was reached. The case's LED had 2 digits and so couldn't show more than 99mhz, so most manufacturers started to stop shipping cases with LEDs.
haha the computer is a 120 so i guess it was RIGHT at that transition period
>>9
I used to have a Pentium 75MHz, but I seam to remember turbo had long gone out of fashion by then, mine didnt have it.
Why do they call it turbo anyway?
>>11
Because when you push it your computer goes faster. Is it really necessary to ask?
The default is fast though, you push it to make it go slower.
>>13
No, that depends on the computer. On some pushing means faster, on some it means slower.
I think it was a marketing gimmick. Someone correct me if I'm wrong.
One state of the button had the CPU going at full clock, and the other at half. So now the manufacturers had a choice:
Will people buy a computer that has a Slower or a zOMG Turbo button? Don't forget that Turbo buttons became mainstream about the time that Turbo cars were all the rage.
>>15
You're right about it being a marketing gimmick, but they had to call it something. It did have some uses, as a lot of software was heavily dependant on processor speed for its timing, especially games. That's why later on slowdown utilities became necessary to run old games on win9x. It's also why on Dosbox you have a parameter to adjust processor speed.
Not that there weren't exceptions. Most office software would only benefit from higher speeds. Alley cat, a CGA game from the early 8086 and 286 days, was programmed well enough that it could still run normally at CPU speeds of 200MHz and higher.
Slowing down a computer can still be desireable today. If you cut the clock cycles you can cut the heat dissipation, potentially allowing the computer to run without all the loud fans necessary to cool components in modern systems. Would you buy a computer that has a Silent mode button?
Well they should just cut the dishonesty and marketing gimmicks and call it a "slow" button if they do include it.
How can it be a "slow" button when, if pressed, makes the computer "go faster" using magical megahurtz?
>Would you buy a computer that has a Silent mode button?
Intriguing question. Yes, I would. The fans on the computer I built are always running, regardless of its activity level (I tried setting on the intelligent fan manager thing in the BIOS, but it doesn't seem to help). I'd gladly have a button to turn the fans off and quarter its clock rate for times when I'm not doing intensive work, but I want it to be done in silence.
Or get fans that adjust their speed as dictated by the temperature coming from their temperature sensor? Thermaltake make some like that, iirc.