So if I wanted an S processor...

[coolpurplefan]

I was looking at the Intel i5-4690S which is 65 watts maximum. I was thinking this is close to the 54 watts of the dual-core models, so why not? I'm not familiar with turbo on CPUs. When you're playing a video game or rendering, does the CPU automatically go up to 3.9GHz?

 

[drescherjm]

I was looking at the Intel i5-4690S which is 65 watts maximum. I was thinking this is close to the 54 watts of the dual-core models, so why not?

Remember these CPUs are not about saving power but limiting the heat output. Unless you have a ITX build you most likely will be better off with a non S processor that you can underclock / undervolt yourself if that is your wish or let it run at full speed when it wants and let it go back to idle faster.

When you're playing a video game or rendering, does the CPU automatically go up to 3.9GHz?

I would say maybe for a video game but not for rendering since rendering will probably want to use more than 2 threads.

 

[MrCaffeineX]

If my understanding of Intel's Turbo Boost 2.0 is correct, the processor will automatically clock up to 3.9GHz on a single core when there is thermal headroom available. The other cores may clock up as well, but not to 3.9GHz, if there is a load on multiple cores simultaneously.

 

[dragonstongue]

http://www.intel.com/content/www/us...ology/turbo-boost/turbo-boost-technology.html

http://www.intel.com/content/www/us/en/processors/processor-numbers.html
so K is unlocked
S Performance-optimized lifestyle
T Power-optimized lifestyle

As far as I knew you could always drop multipliers/bclk but only K variants or tricked out boards will allow the multi to go up.
Anyways just looking at the 4690 as an example
http://www.intel.com/content/www/us/en/processors/core/core-i5-processor.html
4690K 3.5-3.9 88w
4690 3.5-3.9 84w
4690S 3.2-3.9 65w
4690T 2.5-3.5 45w

Far as I recall Ivy and Haswell chips do tend to hit their turbo more often for many reasons. However, they also get quite hot, so I would guess the chip that stays cooler will more often then not be able to turbo more. So, if you took that expensive K chip and clocked it down to say 3.0-3.7 probably could nail down its TDP to somewhere in the 60w range or less so it would run cool and use much less power overall, while still being able to clock up if ever needed.

Also TDP is not max power, according directly to Intel Thermal Design Power (TDP) represents the near maximum power a product can draw for a thermally significant period while running commercially available software. * System and Maximum TDP is based on average case scenarios. Actual TDP may be lower if not all I/Os for chipsets are used.*
So it is near max power (more often the power will and can be less or exceed this by a small or significant margin) where the thermally significant period comes in is much easier. 65w TDP, if the cpu is loaded with proper software and ones cooling system can dissipate this heat then 65w worth of cooling potential is what is required.

So TDP does have an aspect of power usage however, it means more from the cooling side of things.

 

[Cozmo85]

All the S cpu does is throttle itself i believe. Its not actually more efficient.

 

[unclewebb]

Intel's low watt line up is mostly just regular processors that have been locked down and throttled to limit their power consumption.

There are a couple of registers in the CPU that can be adjusted by the bios or by software to limit CPU power consumption. No need to spend extra money on a low watt CPU. Here's what a 47 Watt mobile CPU looks like after it has been limited by adjusting the PP0, Primary Plane, power register.

http://i.imgur.com/2kvFfZQ.png

The limit is set to 15 Watts for the cores. The rest of the CPU is consuming about 3.9 Watts so the entire CPU Package is holding steady at just under 19 Watts. If you increase the number of threads of Prime 95, the CPU will automatically slow down. When you decrease the number of threads, it will speed up, all the while keeping power consumption just under whatever limit you have set.

When Intel releases these various models, all they are doing are adjusting the power limit registers. On the locked CPUs, these limits are set in the CPU and can not be adjusted higher. You can convert an unlocked K CPU down to a very low watt CPU if you like but it is not possible to go the other way.

 

[dragonstongue]

http://forums.anandtech.com/showthread.php?t=2136829 in relation to binning.

In other words declocking and downvolting. To say S class are only throttled is not quite true as they like most chips are part of the binning process. Don't forget making/binning is heavily automated so I would assume as sophisticated as Intel seems to be, am quite sure the testing is indeed extremely thorough.
*run chip at x speed it needs x power is it fully functional, if not go to step 2 reduce speed if cache and such is still fully functional etc*

As not all chips can run high speeds so the inverse is also true, at least if they want to make sure it will hit a specific TDP at a specified clock range with a power level. Obviously Intel/AMD etc tests their chips quite a bit or would not have so many variants or models in the first place, not to mention when you produce many millions of these chips you want to maximize profits so generally the lower clock/wattage parts they use for given product segments failed other ones, i7 failed cache or cores become i5 and so forth.

I do know from first hand experience, just dropping the clocks from say 3.2Ghz to 2.6Ghz reduces heat and power a pretty drastic amount, heat wise only 2-4c above ambient vs 10-15 as an example, so I would assume with all the fancy design built into these new Core i family they must be able to do very nice power saving by taking a high speed chip and clocking down like this, though if one simply does not need the raw amount of performance, just go for a lower clock speed chip that has less overall cores to save the most power i.e core i3 u or Pentium derivative and clock down to save a great deal of power, and ehy they still will have turbo to clock up if they need it