Turbo Boost in i7s?

[ElectroGoofy]

Hello, all.

I am wanting to buy a new laptop (not sure if that will happen, though) sometime in the next few months, and am trying to get caught back up on some of the newer stuff that is out on laptops.

Ok, as for the point of this post, I was wondering if somebody could shed some light on Turb Boost in the i7 processors. I see all these processors with like 1.6ghz, but they have turbo boost up to like 2.6 or so. This is sort of like automatic, on-the-fly overclocking as you need the extra performance, correct?

I don't know what it is about it, but for some reason I would think that a fixed clock speed would have better performance... what does it take for the clock speed to ramp up to max? Do you need to be pegging it for a certain amount of time before it will increase the multiplier? Also, how long after this does it start to underclock itself? (I am wondering if it constantly jumps up and down, or if it sort of slowly increases or decreases).

Anyway, any other information on Turbo Boost would be very welcome

Thanks!

 

[hunter315]

The turbo speed depends on the number of threads that the main process is using, the more threads the lower the turbo boost.

Turbo kicks on once you load it up with something that could benefit from it(if you are only loading up to about 40% on any core then it wont kick in since it wont help much) and it will stay on as long as the temps stay in the safe range which is indefinitely as long as they didnt give the system a crappy cooling system. Its just another extension onto the power saving features normally used, except instead of downclocking, it keeps it slightly down clocked and only boosts it up when needed.

 

[ElectroGoofy]

The turbo speed depends on the number of threads that the main process is using, the more threads the lower the turbo boost.

Turbo kicks on once you load it up with something that could benefit from it(if you are only loading up to about 40% on any core then it wont kick in since it wont help much) and it will stay on as long as the temps stay in the safe range which is indefinitely as long as they didnt give the system a crappy cooling system. Its just another extension onto the power saving features normally used, except instead of downclocking, it keeps it slightly down clocked and only boosts it up when needed.

Ok, for the first sentence there, it sounds like you are saying that if one process is using all the threads, it will stay at a low clock speed... am I understanding correctly? If this is true, wouldn't an i5 or something that has a standard clock speed of, say, 2.6ghz outperform an i7 @1.6ghz with turbo boost to 2.6ghz? (In this sort of situation, at least).

Also, I know it would depend on many factors, but how much of an increase of battery life would this really mean when compared to another processor without turbo boost? (But with the same ghz as the max turbo boost of an i7).

Thanks for the reply, btw

 

[rvd89]

An i7 has 4 cores, with hyper threading to add another 4 virtual cores. An i5 has 2 physical cores, with HT to a total of 4. With certain programs like video/audio encoding, where all cores can be used, an i7 will work with all 8 threads at 1.6gHz compared to an i5 with 4 threads at 2.66gHz. Can you see that the i7 wins in this senario?

However for gaming where usually up to only 2 cores are used, the i7, which I take to be the i7-720QM will turboboast up to 2.8ghz while the i5 to 3.2ghz. So since the i5 clock speed is higher, it performs better in gaming.

 

[jaguarskx]

Additionally, not many consumer market programs make use of hyperthreading and there are no games that takes advantage of hyperthreading.