The PC turbo button mystery finally solved!
Вставка
- Опубліковано 13 лют 2023
- An example of how to settle a long-running Internet debate and bust a revisionist history myth, by reading manuals, books, and magazine articles, doing some research, and confirming it with your own tests. C'mon folks, it's not that hard!
Time flow:
0:12 First, history lesson
2:37 Zenith Z-148 PC
3:48 A typical 486 PC
10:23 Gateway 2000 4DX-33
11:52 5x86 with fake cache
15:07 Turbo buttons EOL
16:01 Don't take my word for it!
Note: This video was originally uploaded in October 2022 as an unlisted, updated version of the initial release of this video, which used a portion of text-to-speech synthesis which some viewers didn't like. I decided to make this version public, which is why it shows up as being published in February 2023, and retire the initial version of the video.
Intel 486 SL Microprocessor SuperSet Data Book:
www.datasheetarchive.com/pdf/...
#turbo #cpu #vintagecomputing - Наука та технологія
*Note:* This video was originally uploaded in October 2022 as an unlisted, updated version of the initial release of this video, which used a portion of text-to-speech synthesis which some viewers didn't like. I decided to make this version public, which is why it shows up as being published in February 2023, and retire the initial version of the video.
I thought I recognized this as a repeat… strange thing it was public when I saw the original video
The turbo button selects between two speeds, therefore it can speed up or slow down the machine depending on perspective. As several commenters have stated, many clone brands had the button or indicator light reversed. If the default is full speed then it is semantically correct to say that the turbo button slows down the computer(especially on janky hardware that reverses the indications).
Though I agree that any complete article should explain both situations rather than making half-truth blanket statements.
@@mytech6779 turbo on - normal speed
Turbo off - run slower so old games would run at a normal speed ie. Pac-Man you do not want the ghosts to have super speed around the maze
Great video as always dude, cant say anything but that this settles any reasonable debate about the "turbo button", except for maybe semantic arguments. But the technical side should now be crystal clear to most who has seen this video.
Again, big thanks, these are the kind of videos we need more of.
I thought I was going crazy lol
you have an extremely good narrator voice and you have clearly worked hard to remove all verbal pauses . i like your voice a lot, please don't make me listen to TTS again
Jordan Peterson mixed with Kermit
He sounds like a friend but older.
@@ac3d657 people always say Jorden Peterson sounds like Kermit….. this guy sounds like him WITHOUT the kermit
@@bizzzzzzle Tastes great less filling 🥧🍰🙂
@@bizzzzzzle I don't know this jordan peterson guy but I would pay VWestlife like $20 to do a cover of rainbow connection
Yup. I was always confused when UA-camrs said that the turbo button, when pushed in, would slow down your machine. I've tried explaining that I would play Wolfenstein on the college pc and the turbo (when on) would run the game much smoother. I was always told to go do my research as it was a known fact that the turbo button slowed your machine down. Even though, like I said, I'd actually lived it XD
@@elemar5 The one in the video does seem to have two sets of contacts, normally open and normally closed, connected to three wires though. In that case, depending on how the switch is plugged in, Turbo mode is either switch pushed in or switch out. Of course that also depends on the board design, whether it expects an open circuit for Turbo mode (like the late 486 and Pentium boards in the video) or closed, like the older boards.
Regardless, when the LED is on the PC runs faster.
@@elemar5 I haven't built as many PCs but still quite a few, plus I've got a background in electrical engineering.
How would that work? The average turbo switch was a plain single-pole switch that connected the two wires when depressed and broke the connection when not. Depending on what the board expected, the CPU would behave accordingly. Reversing the connector doesn't change anything, the circuit is either closed or not and whether the button needs to be in or out for closed is mechanically determined and impossible to change without disassembling the switch.
@@elemar5 Sounds like your memory is a bit hazy. It's impossible to just reverse two wires from a switch and have it go from normally open to normally closed. That's why some have 3 wires. Also the LED will not light up in non-turbo mode by reversing it. A diode does not work that way and more importantly, an LED will not illuminate with zero Volts applied to it.
My mind also went straight to memories of Wolfenstein in high school. I remember the issue with the button not always being in the same position when the light was on. Turbo was definitely smoother. Good memories.
@@Ragnar8504 Regardless of what an "average" (guessing you meant "typical") turbo switch might be, there were switches that could be installed two ways. Since you've got a background in electrical engineering, you clearly didn't actually watch the video, or you'd know exactly how it would work. The switch in the example machine had three wires, in other words it was a dual throw switch. No reversing of the connector, changing which of the three pins of the connecter connect to the two pins on the board.
I somehow managed to be ass-deep in computers through the entire "turbo button" era and never once knew about that keyboard shortcut. I have no idea how I missed that.
Don't beat yourself over this, flapjack. I didn't know about the keyboard shortcuts until now. I had my PC with a 486 DX mainboard and I know how to use the button on the case, not the keyboard shortcuts. I only started to use keyboard shortcuts when during the internet age, although I was taught the 3 finger salute (ctrl + alt + del) by my former neighbour if I needed to restart the computer.
I had my first turbo mode PC in and around 1996. All I ever did was run benchmark tests because I had no other use for a PC. Life was so simple back then.
How much did it cost?
Why did you even have a PC? :-)
@@queenannesrevenge3770 $3,500 Cad
@@alexmckee4683 Had to keep up with the Jones.
I remember my first pc in 1990s. Odd design back then but guess they were aim at offices
This version is certainly better than the original upload. Using the TTS may have been a time constraint, but honestly, your voice works much better for narration.
@@jfrarex get a life
Which TTS was used? Something like eleven labs AI TTS is hard to tell from a human. It didn't exist when this video was originally created though.
I honestly never knew the turbo button was even a mystery. Thought this was basic knowledge for anyone who grew up in the 90s
Correct.
I was around when the turbo button was used in anger :-) Some early software couldn't run past 8mhz without problems and the turbo button allowed the computer to be slowed down to accommodate that software. Turbo was a marketing term to explain backwards compatibility.
My dad used to turn the turbo mode on when he was doing work in Lotus123.. I told him it didn't do anything for that, but he was sure it made him work faster - not the software, him, hisself.
I'm glad PCs grew out of that phase - the last 3 PCs I've built for him and my mom over the years since the early days were excellent for their needs, and the only complaints they ever had was that they had to get used to the desktop resolution making things look 'too good', and 'not blocky enough', and occasionally they would accidentally 'delete a program' by which they meant they deleted the desktop shortcut. :p
And yet we still find occasional games where parts of the logic are dependent on framerate. Which means some developers spend 40 years and still haven't noticed that different people have different systems with different performance.
I’m just wondering how he thought pressing a button on a computer would make him work
faster
@@plumjet0930 Well, it may have something to do with being young and goin' wild during the 60s and 70s when LSD and the hippie thing was raging, but I honestly don't know either.
Only 10 seconds longer for the authentic VWestlife narration. I've got an extra 10 seconds for you any day :)
Also in the 80s anything with turbo on it instantly made it better in the minds of people in the 80s, you could get some Turbo sunglasses or a Turbo vacuum :)
Great video btw, liked your voice in the video also.
Just like how in the 90s everything got a "2000" added to it to sound advanced and futuristic.
Lol I remember "Turbo Black" paint. Ed Mcman announcer voice>>>
Guaranteed to make your car more efficient. Everyone knows! Black is the fastest color. Now we at our cutting edge labs in So Cal. "2001 tech unlimited" have gone and Turbo'd the color black for double the performance ! "Turbo Black paint" for the discerning enthusiast. Leave em in the dust, and asking..
Guy on street>>> Hey buddie! ..How dooo yooou doooo it? Im so lame and small , your super cool! You are MEGA cool and fast, its like dark lightning burning my eyes! Announcer...always leave em wondering Wink! TurbOOOO ! BLLLLAAAACK! The mans, mans, man, knows!
A turbo vacuum is at least a bit closer to what an actual turbo is about.
Lol turbo sunglasses. I imagine they would look like Tom Cruise Top Gun glasses with a button on the side 😂
@@catsaregovernmentspies dat Gateway doe
I've never been so happy to hear your voice since subbing to this channel, the TTS voice was nice, but it reminded me of those old pc commercials from the 90's, thank you for uploading another version with your own voiceover, it's much appreciated!
Had a 486 clone, about 30 years ago. And my turbo button was active when pushed in. And I compared it by turnin' it on and off while runnin' a screensaver. The difference was usually readily apparent.
my 486 had a simple button with no locking function, luckily the case had a built in led panel displaying the current clock speed
We had a 486 too and I remeber it was going from 8Mhz to 40Mhz with turbo mode enabled.
Turbo mode button reminds me of the amplifier dial that goes to 11 in the Spinal Tap movie, where the narrator says why don’t you just make the 10 louder and use a 10 selector dial.
Love your voice as a narrator, you have a unique sound and accent that lends itself really well to it.
"Proves" can be used in sentences such as "it proves fun", meaning "it turned out to be fun" or "it reveals itself to be fun", so I think what they were saying was "When you do this, it reveals itself to be (an unsurpassed) 60% faster machine than others".
So rather than being a mistake, it's probably just a bit of outdated grammar.
Interesting, I wonder when that change occurred
i prefer your voice to the tts but honestly great job for listening to everyone and remaking the video even when you didnt have to just for your fans. this is my first time watching but it seems like you really care about you community and im excited to become a part of it
In the mid 90s, at my office we had PCs that, instead of a light for the Turbo button, had a small display that showed "HI" and "LO" for speed. A couple of people at my office argued back and forth about which one was faster, "H1" or "L0" and were astounded when I told them that it was shorthand for "High" and "Low."
I guess they had never used a fan or heater in their lives to not know that!
why is this video coming back after 4 months?
It wasn't "re-uploaded" it was uploaded as unlisted 4 months ago (linked to from the Text to speech version), and then this narrated version was made public 14th Feb.
To make things MORE confusing, on cases with the "speed" display, often times there was NOT a Turbo LED. SO, IF you reversed the 3-wire connector but had the button pressed in, it would show the Turbo Speed, but would actually be running at the slower, non-turbo speed. I had to correct quite a few customer builds because they had the connector backwards!
imagine your modern computer had a turbo button you hit it and windows crashes🤣
@@raven4k998 Funny how PCs went from no speed control to 2-stage speed control to a whole range of possible speeds with software control!
I like how he explains what he is doing because I cannot see but I could imagine what he’s doing. I was born in 1984, so I really don’t know much of those old computers but I do know a lot about Windows 95 and up.
Yay! Thank you for uploading this video with your narration, always love to have your videos in the background and the TTS was a bit off.
Thank goodness you FINALLY solved the mystery. I don't know I was thinking when I read about this in my computer manual or my PC Magazine subscription in the 80s. Thank you again for your hard work bringing this back our attention.
My first family PC was running Windows 95 and had the lock key and the turbo button. I remember the Turbo button would make the machine noticibly louder, so I had always assumed it just sped up the fans to cool the CPU better. This was back in the day with those giant hard disk ribbon cables and case ventilation was basically a meme. 😂😂
I am remembering the sound of those tiny case fans. They sounded like a Cessna taking off at 100 yards.
You bring out a lot of old memories from back then. Thanks for this video great explanation of the turbo function and some older pc's in general. 👍
Haven't thought about that 3 wire turbo button connector for years! Great memories, great channel 👍
I swore I saw this video once already but then I realized you went back and read the narration in the first portion. Hey this was a good video so it was worth another watch
thank you very much for oponing my eyes to this ancient mystery!
(excellent video.)
I didn't hate the text to speech voice (especially since it was only one part of the video), but your actual voice is certainly better!
Thank you for uploading this with your own voice. I couldn't stand that other one.
What a walk down memory lane - thanks so much for publishing this.
Excellent video. Very well put-together and succinctly narrated.
I don't know why I watched this as it just confirms what I probably knew 30 years ago but had forgotten and there is now no need to know this information. It is a good video and entertaining for some strange reason, maybe because it confirms I once knew what I doing. Keep up the good work!
Brillant reupload Kevin. Last one was fine but always better when your voice is heard :). Informative, funny , unpretentious and direct. Perfect combo. 👌
Thanks for the various benchmarks! Back when 486s were actually still in use I was led to believe that the button only changed the CPU speeds on 8086/8088 machines or possibly 286s. On later machines it just did things like deactivating the cache or coprocessor, or so I was told. Learned something new today!
Great job man! Thank you, sincerely. I'm embrarrassed my intense autodidactic curiosty failed to motivate me to answer this question on my own in 1989. Feels great to get closure to something I forgot I always wanted to know.
7:33 Thank you so much for clearing this up! I had a Compaq 386 25Mhz in 1992 which included the LED indicator, but it always puzzled me that when pushing the button the PC actually slowed down. Sometimes it just takes 30+ years to solve a mistery!
Always a good day to hear the 8088 processor mentioned. Brings back a lot of memories from Community College computer lab in the mid 80s. Thanks for the videos.
Well worth the re-up. Your narration matches these machines very nicely.
It wasn't "re-uploaded" it was uploaded as unlisted 4 months ago, and then made public 14th Feb.
My 486 turbo button only had 2 pins, and the motherboard defaulted to "fast" mode. Without the button connected at all, the computer would run at full speed no matter what. With the turbo button connected and pressed in, it would slow down, and this would happen regardless of the orientation of the connector on the header. Maybe it varies computer by computer, but that's how mine is set up, and there is literally no way to configure the turbo button to make the computer faster, the ONLY option for my machine is for the turbo button to slow down the computer
This is exactly the problem we had in the early 90s when I did PC support and new PC builds. We always preferred the Turbo button to be pushed in for Turbo mode and that was the default except when we had motherboards like you mentioned. In those situations we wished the cases said Turbo Off. We provided labels if the customer wanted to change what the case said.
It's the issue of the combination of the case (button) and the motherboard. The whole point of three-wire setup as was shown in the video is that one pair of wires works as "normaly open" and the other pair of wires works as "normaly closed" - that way you could simply choose by moving that connector one pin to the left or right.
However when you have case that has a "normaly open" button and motherboard that is set-up so that open = turbo, then yes, pressing the turbo button (closing it) will switch the motherboard to slow mode. You would have to replace the actual switch in the case for a "normaly closed" one. Or maybe there is an unused pin on that switch that acts as a "normaly closed" pin, so it would be enough to resolder the cable on that end (or move the wire, if there is pin header on that end as well).
@@Tomas_Stec Yeah but the one thing you can't do is make the PC run slower when the LED is on (and that wouldn't make any sense anyway, turbo suggests higher speeds). It might simply be a poor choice of words for expressing the fact that turbo mode was indeed the default speed of the CPU and disengaging it made the computer run slower though. Or someone put it like that and someone else misunderstood it.
@@Ragnar8504 One NOT gate + some stable voltage which you can steal from the "power on" LED and you can have the turbo LED working inversely. OK, it's a bunch of additional components.
@@Tomas_Stec Of course it can be done. Not without careful planning and a bunch of extra parts though, not something that's likely to be done building a simple standard PC.
I am amazed that your old PC collection (I actually used some of those way back then :)) is in very good and working condition, but you still have the printed manual for the motherboard! I would be glad to have such collection!
Thanks for the link - the video with your real voice is much more pleasurable!
Thankyou, so much! This is so very much appreciated.
My only issue with the TURBO buttons was that they were dangerously close to the RESET button on many cases... Means that when one thought he can just get down to the tower case hidden under the table and push it by memory... ooops... there it was 🙂
That's why we left the reset button unplugged from the main board. You can always do ctrl alt del or power switch if you need to reset.
Remember the old System 7 Macs from the early 90s? Macs did not have a floppy disk eject button. But they put the damn power button right next to the floppy disk slot. Many unfortunate outcomes from that.
I love the idea of people being like "yeah... time for Turbo! Damn it!! No! Not reset!"
One time my reset button got stuck in. I couldn't figure out why my pc wouldn't turn on or do anything at all for a good 20 minutes 😂
Yeah, someone pointed the narration voice. That’s part of the appeal of this channel. Kudos as always🎉
I worked for an HP dealer when the 80486 machines came out. The ad campaign featured HP Vectra computers with stickers all over them like Grand National race cars.
I remember the first computer I saw with a turbo button. Back then most computers booted to DOS and a menu came up first. From there you selected a program or windows if that was installed. Most machines struggled to boot WORD in less that 20 seconds. The first time we booted WORD with the turbo button in the thing loaded in 3-4 seconds. I thought how do they make them so fast. It’s funny to think of that now.
Hilariously Word takes me 10-15 seconds to boot up with my modern laptop.
I'm glad you made this version available to us. Until I watched the TTS version I didn't realize that your voice is a big part of what gets me engaged with these videos :)
My first computer, a Magitronic XT clone, had a blue turbo button on the front. Made playing Digger and Ribit (in your video!) much easier 😁 Excellent video! 👏
What a flash back. Love it. Thanks
Watching your videos about all these PCs from the 80s and 90s brought back happy memories. ☺️
You even had a clip of MuchMusic Video on Trial here. Certainly a blast from the past. That was a good show.
Regardless of how the button is configured I always considered the turbo button as a means to slow down the computer because with turbo enabled the CPU is simply running at its designed speed. Disabling the button was to slow down the computer to resolve issues. If the turbo button were designed to overclock the CPU or to enable another piece of hardware like a coprocessor or something then I would have considered it to be an actual turbo button to speed up the computer.
I feel like the turbo button is more akin to a button in your car that would turn a governor on and off for the engine rather than a button that would toggle the boost from a turbo on and off. I just think the button was poorly named.
Our first computer was a 386 that had a turbo that bumped it up from 20 to 25 Mhz. We typically pressed it the same time we pressed the power button to boot the computer up and never really thought about what it did. Thanks for the video.
The only channel that covers most of my hobbies. Computing, audio video, electronics. I hope u do on motorcycle review soon.
This is a much needed video. You must watch it. ☺♥
One thing to add: When the case had those 7-segment displays, what was shown on those was configured by… A pin header and bunch of jumpers on the backside of that display. So with a manual for the case, or just with a bit of experimentation, your 33-MHz 386SX could show 99, PC, FU, or whatever else you could think of with that 14 segments. (Well, maybe some cases had it hard-wired, but this was the situation with our first PC at home.)
I had that exact model Gateway. It was a really solid computer at the time. It defaulted to turbo and I basically never turned it off.
Yeah, our first PC was noticeably faster with the turbo mode on. It was never in question in our household. Great upload, thanks! Looking forward to more.
Wow those sounds brought back some memories, lol. Never knew about the keyboard combination to toggle the turbo mode.
This REALLY needed to be done, so many crossed wires on the subject!
Absolutely good video 🔥
I love this channel!
I remember watching that creed clip on tv when it originally aired. That's how I know i'm getting old.
Great history lesson! Glad to know just exactly what this button did.
Back in the mid 90s I used the Zenith Z-148 PC for practicing my typing with typing tutor IV program.
The one I used at the time had the internal hard drive instead of the additional 5.25 floppy drive.
Thanks. I thought I remembered it working the way you show it does.
I love how you added a retro 80s style to this video, to emphasize the point... very artistic.
I'm so glad you made this video, and with actual contemporary references to what the turbo button is actually supposed to do. I've had this discussion with several people in my club and they always take out their phone and point to some "doggone" Gizmodo like article saying turbo button "aaaccckkktttuuullly" slows it down. The funny thing is the people that are telling me this are so much younger than me and have likely never even owned or used a computer that had one. Well I have owned and used turbo mode computers and all of the ones I had (I had 4 computers that had them) the turbo mode switch was correctly wired to speed up the computer when activated by a button press using ones middle finger. Its likely more commonly pressed with an index finger. But I would routinely use my middle finger to press the turbo mode activating button as my middle finger is the longest of my fingers and the position of the button on most of the computers I had was such that using my longest finger, the middle one, was the most sensible finger to use.
The "turbo" button is a limiter. You're not enabling turbo when you press it, you are disabling a limiter. Meaning that the only purpose of the turbo button was to give you the ability to make your computer run slower. The turbo button is for slowing down your computer.
I had my Turbodisplay hooked on my HDD indicator. Set the jumpers to read Hd on the display and -- for idle. Nice fancy effect.
you have a good voice for videos!! don't waste it on TTS!!
I am so glad i subscribed to your channel! I've seen this numerous times especially on wikipedia that information was either plain wrong or faulty. While knowing very well in the back of my head that i've read something different years ago in a magazine or manual. Of course some magazines were also wrong or published rumours and hearsay but seeing multiple manuals and then something very different on wikipedia is just questionable. Also made me think about the "toaster incident" on wikipedia.
PC builder since 1977:
Hard-drives weren't as peppy or reliable as one may want.
Some drives worked best within a narrow range of temperature, or only in certain orientations.
A 'warm-up interval' with several attempts to Boot was just a thing we all expected to do in the morning.
Maybe it was the surplus drives we were using?
Turbo allowed better 'fit' between MOBO speeds, drives and driver controller(s).
Booting was a fine art for many years, and sometimes slowing down was the only way to maintain stability.
I can confirm this.
Great video, can’t believe I remember.
This video is the best. great job
Oh nice a updated video! Anyways I always likes videos about old computers
I have this old keyboard that needs two adapters to use with my new PC, and it has a Turbo button in the middle of the arrows. The eight arrows. Yeah, it has diagonals. I love that thing.
Those startup sounds are so nostalgic.
"the book"
I love that sentence:D
Thanks for that great info.
Once upon a time, being a kid, I also had PC with turbo, but I was always jealous of my friend who also had such BUT including the speed indicator:)
I appreciate that the wikipedia article for the turbo button is correct now, and it links to that Intel datasheet for citation.
"It doesn't speed up your PC if you press it, it slows it down if you _don't_ press it" is a very good way of putting it!
It should never have been called turbo in the first place, it should have been called "Slow mode" or something and worked accordingly.
I appreciate this so much I watched the video again
Anyone else love the transition sound? Because it's perfect
As a kid, I was always curious the purpose of said button, now I finally know (course back then I wouldn't have understood it even if I did hear this). I also remember that CPU number display. I loved seeing that and always wanted it on my computer, because it looked cool
I think you just relieved a headache I suppressed 30 years ago! 😂😂😂
Hi, another great video
This is like the black magic of computers, being old enough to have purchased C64 new and every other computer almost every second year, then a life time of PC upgrades
I explain to people at the time many games or software was speed sensitive, with 286/386/496 you have the option to slow back to stock XT 4.77m
Nortons info is good, but so it making them play frogger !!
I explain wired correctly your fast machine is full time turbo or fast on , only when you want it to slow down it is turbo off or slow
The first machine that did not have the turbo connector on the mother board was a Pentium 100
Regards
George
This is definitely a lot better, dude :) .
Yet again, another successful debunk. Well done sir! gotta love it when you put the so-called "know it all" channels in their place.
What are you talkin about? He didn't debunk anything. It's all a marketing spin. The Turbo System was an artificial limiter that slowed your computer down until you press the button or hit the key command to remove the limiter. While you were told you were turning on turbo you were actually turning off the limiter. That means the only purpose of the Turbo System was to be able to make your computer run slower.
@@dmac1259 😴 other UA-camrs have said the opposite for a long ass time, this corrects those people and therefore debunks the crap they're saying to their followers. I watched the video. I understood what the button was for before watching. What I didn't need was you being hostile for zero reason. 🙄
He didn't debunk it at all. He says around 16:00 that the purpose of the turbo button was to slow down the cpu because when it's off your cpu runs slower. It's a combination of marketing and also compatability with games that ran off of clock spees.
Yes. Because a lot of software used the CPU itself to limit their processing speed, running at full tilt at the max speed of the processor with no software speed management for whatever processing the program did. hitting the turbo button didn't speed up your computer, it slowed it down. I remember playing with the turbo button on my PC clone and the game Robotron. In slow mode, the game ran properly. At high speed, you'd start the game and the robots would just blink to the middle of the screen and you were dead.
I remember those early el-cheapo imported 8MHz mother boards, so many were dodgy and crashed/freezed frequently. If you wanted to do serious work (as opposed to playing games) you were better off in non turbo mode.
Luckily they eventually got their act together with reliable fast boards.
and then I learned about it 25 years later, amazing.
On every PC I had with a turbo buton they had LED's. And thank you for a brilliant video
Lol my grandma used to tell me never to press the turbo button or it would burn up the computer. I just facepalmed and said "that's not how it works.... It's for older apps"
Depends on how the button is configured but usually it did slow the machine down when pressed in.
Man that brings back memories and so many hours learning and building. All obsolete info now.
I had both a 8088 and a 80286 PC's in the VERY old days. Many games and apps made for XT's were unplayable or unusable on 286's because what you saw was blurred lines or objects by running too fast. Especially the CRT's of the day with primitive phosphors the problem was even worse because it took more time to stop glowing. The turbo button changed the clock to 4.77 MHz . When EISA and PCI buses were introduced you could not change the clock speed that easy
I remember the first PC I had (not including Commodores and Atari XLs, I had a few of those) was an 80286 that I assembled myself. I remember that it had a 4 color graphics and I thought that was awesome! I never really noticed a lot of difference when the turbo was in or out. I built just about every version of PC up to the newest Gen 12 PC that I currently have. I think I still have an IBM 8086 in the attic, along with a Timex Sinclair, still in the original packaging.
I have a DOS PC with a K6-2 on it. The mainboard has jumpers to set the CPU frequency, but no turbo connector. So I did a bit of testing, and found a good jumper to put the turbo button on. It now actually switches the CPU clock to either 300MHz or 550 MHz.
"IT'S CALLED A BOOK" Well said!
My first turbo system was an 8Mz XT clone. When I had the money I bought a full sized tower for a 286 system that ran at a whopping 16Mz, including a two digit LED speed readout. Who would ever need three digits!?
By that time most if not all motherboards let you configure the system to start up in high speed mode if you wished. There was no actual detection of actual system speed; you had to set the LED panel for hi & low speeds yourself.
I had that tower for a long time; upgraded to a 386sx-20, then a 486dx2-66. By the time I passed 99Mz, I had to buy an ATX case for the hardware. Readouts were rare for ATX systems.
Well I missed the original version of this so I appreciate this upload. I was less bothered by the turbo function itself than I was by the fact that the switch had 3 wires while the header only had 2! So you've cleared that up for me. The question I was really hoping to see answered is what factor the turbo function in-/de-creases the speed by. There's a clue at the end in that it's a function of the CPU itself, but I would love to know whether non-turbo is absolute or relative. I've got enough CPUs that I can find out for myself, so you've inspired me to do so.
Answer is really just it depends on the hardware, the 486 SLC with a turbo control line and internal divider mentioned in the video is a late model 486, earlier ones relied on external hardware (an ASIC chipset by the 386 era) dividing the CPU clock and it was entirely up to the chipset vendor to choose the division factor. Could have been jumper selectable or programmable on some boards too, but I'd wager it was almost always some power of 2 (÷2, ÷4, ÷8, ÷16, etc) because you can get it just by chaining flip-flops rather than having to use something like a PLL.
@18:40 or thereabouts, the Intel datasheet specifies 1/4 or 1/8 clock speeds (depending on the manufacturer, I assume.)
@@Mahashma great info, thanks! Gonna do some of my own tests on this as well.