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I have an Intel i7-3630QM processor in my laptop. Its speed is supposed to be from 2.4 to 3.4 GHz in turbo boost mode.

In reality, will it ever run all cores on full speed (3.4GHz mentioned above) at the same time?

I heard somewhere that this additional 1GHz is shared between all cores in laptops. If the boost is 1GHz per core it's pretty impressive (over 40% speed up). What does it really look like? How long can a processor run in turbo mode?

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Intel Turbo Boost only boosts the speed if the processor is not fully utilized. Their site is pretty vague on details, but I remember seeing that it's designed for when one core is being maxed out while the other cores are sitting idle. If you're using multiple cores, the processor is drawing too much power, or the processor is too hot, then Intel Turbo Boost will turn off and the processor will return to it's normal maximum speed.

All cores will technically be running at the full speed, but you can't utilize all the cores at the same time while boosted or the processor will return to the normal maximum.

Intel® Turbo Boost Technology provides more performance when needed on 4th generation Intel® Core™ processor-based systems. Intel® Turbo Boost Technology 2.0 automatically allows processor cores to run faster than the base operating frequency if they’re operating below power, current, and temperature specification limits.

Any of the following can set the upper limit of Intel Turbo Boost Technology 2.0 on a given workload:

  • Number of active cores
  • Estimated current consumption
  • Estimated power consumption
  • Processor temperature
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I don't think it will return to the normal maximum if more than one cores are in use. I remember it as having multipliers where the max would ideally be applied for one active core. So in his case, if the normal multiplier were 24 (24 x 100MHz) then the max multiplier would be 34. But if two, three or four cores are active then the multiplier would be something greater than 24 but less than 34, allowing for various boost speeds. –  Louis Jun 26 '13 at 5:14
    
@Louis That's entirely possible; That information is more regurgitated from memory when Intel first introduced Turbo Boost, and it's likely that they've refined the algorithm since then. The key is more that while it'll let you push a core past 100%, it won't let you push the processor past 100%. –  Darth Android Jun 26 '13 at 18:50
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Note: I do not take credit for this answer as the information was already posted else-where. I am just spreading it for help.

Source: iPod App ; Intel Channel Guide

Intel Turbo boost;

Automatically runs the CPU faster than its marked frequency (i.e. 2.6GHz -> 2.8 - 3 GHz) if the part is operating under power, temperature, & current specification limits of Thermal Design Power (TDP)

Source: http://en.m.wikipedia.org/wiki/Thermal_design_power

Thermal design power The thermal design power (TDP), sometimes called thermal design point, refers to the maximum amount of power the cooling system in a computer is required to dissipate. The TDP is typically not the most power the chip could ever draw, such as by a power virus, but rather the maximum power that it would draw when running "real applications". This ensures the computer will be able to handle essentially all applications without exceeding its thermal envelope, or requiring a cooling system for the maximum theoretical power (which would cost more but in favor of extra headroom for processing power).

In some cases the TDP has been underestimated such that in real applications (typically strenuous, such as video encoding or games) the CPU has exceeded the TDP. In this case, the CPU will either cause a system failure (a "therm-trip") or throttle its speed down.[1] Most modern CPUs will only cause a therm-trip on a catastrophic cooling failure such as a stuck fan or a loose heatsink.

For example, a laptop's CPU cooling system may be designed for a 20 watt TDP, which means that it can dissipate up to 20 watts of heat without exceeding the maximum junction temperature for the computer chip. It can do this using an active cooling method such as a fan or any of the three passive cooling methods, convection, thermal radiation or conduction. Typically, a combination of methods is used.

Since safety margins and the definition of what constitutes a real application vary among manufacturers, TDP values between different manufacturers cannot be accurately compared. While a processor with a TDP of 100 W will almost certainly use more power at full load than a processor with a 10 W TDP, it may or may not use more power than a processor from a different manufacturer that has a 90 W TDP. Additionally, TDPs are often specified for families of processors, with the low-end models usually using significantly less power than those at the high end of the family.

The dynamic power consumed by a switching circuit is approximately proportional to the square of the voltage:[2]

(where C is capacitance, f is frequency and V is voltage).

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