PC CPU with Turbo functionallity , enlighten me !

[s8n]

hi RB members , ive been looking into getting a new PC for the future

I see that some of todays CPU's have a Turbo function that say it is 3.6Ghz default and 3.9Ghz with Turbo.


How does this work exactly ?........


any info helps

s8n

[D.D.D.]

Whoa~ That reminds me of the "turbo" feature on 386s and 486s IIRC. And IIRC it did absolutely nothing (at least on the school lab PCs).

[neilencio]

it's kind of like a reverse throttle. Whereas the throttle function downclocks the cpu when idle, Turbo boost increases the cpu's clockspeed under certain situations (I'm not sure what the conditions are, as I have yet to touch an i-series or that new AMD equivalent. Does it kick in under full load?).

[neilencio]

Whoa~ That reminds me of the "turbo" feature on 386s and 486s IIRC. And IIRC it did absolutely nothing (at least on the school lab PCs).

LOL, I remember those well. My college school lab had similar PCs, but some of them do have working turbo buttons. It probably just wasn't noticeable because we only used the PCs for qbasic, foxpro, and turbo pascal. There is a battle chess and a golden axe installed, but we don't have the manual so we can't do anything about the "turn to page 26 of the manual and type the word blah blah" prompts.

[samsonlonghair]

My old IBM clone had a "turbo" button back in the day. It did absolutely nothing. I guess it's just a gimmick.

[gennss]

If the turbo button actually was set up to function on the PC. It should've always been on. It is turned off when using older software such as games that rely on the system clock rate for timing.

Games obviously no longer use this for timing, however, trying to play pacman designed for an 8086 or 286 on a 486 would make the game run too fast to be playable. Hence the reduced speed functionality.

[Hatta]

Yeah, back in the day the Turbo button actually underclocked the CPU. These days what's called "turbo" is a feature where they disable or underclock unused CPU cores so they can temporarily overclock one core while staying within the CPU's total power dissipation ability.

[isiolia]

it's kind of like a reverse throttle. Whereas the throttle function downclocks the cpu when idle, Turbo boost increases the cpu's clockspeed under certain situations (I'm not sure what the conditions are, as I have yet to touch an i-series or that new AMD equivalent. Does it kick in under full load?).

Basically, it's a best of both worlds design.

The general trend, as multi-core CPUs have proliferated, is that, at a given price point, you typically had a choice of more cores or a higher clock rate. For example, with Core2s, you could go with a Core2Quad for better performance in heavily threaded apps (or multi-tasking), or you could get a Core2Duo for higher stock clock speeds, and thus more performance in less threaded applications (such as most games at the time).

With the current CPUs that include Turbo Boost, you don't need to compromise. If the CPU's logic senses that you're not actually using all the cores, it can shut some down and run the rest faster.

Effectively, you can read it as "runs all cores at x, runs a single core at y".

[pakopako]

If the turbo button actually was set up to function on the PC. It should've always been on. It is turned off when using older software such as games that rely on the system clock rate for timing.

I remember that. I still have my old x86 (as a vanilla Ottoman). I used to turn the Turbo off when playing Grand Prix Circuit‏ so I could handle the hairpin turns!

These days what's called "turbo" is a feature where they disable or underclock unused CPU cores so they can temporarily overclock one core while staying within the CPU's total power dissipation ability.

Wait, so modern Turbo actually overclocks the CPU? (Granted, it is reducing a multicore CPU, which is pretty awesome.)

[isiolia]

Wait, so modern Turbo actually overclocks the CPU? (Granted, it is reducing a multicore CPU, which is pretty awesome.)

Eh, kinda. Since it's within normal parameters it's hard for me to think of it as overclocking and more as a form of throttling.

Turbo is normally disabled if you actually are overclocking.