Become a MacRumors Supporter for $25/year with no ads, private forums, and more!


macrumors 6502
Original poster
Oct 12, 2009
How does it determine when to switch over to the faster speeds? Is there a way to have always be at 2.6GHz?



macrumors 601
Jul 1, 2004
How does it determine when to switch over to the faster speeds? Is there a way to have always be at 2.6GHz?


I'm not exactly sure how it determines how to switch, but it would most likely be due to the CPU utilization at the time. It's just built into the design of the chip, much like idle power states and hyperthreading.

Keeping your CPU utilization at 100% for each core is a good way to have it stay at 2.6GHz. But your battery life will suck.

Coming up with a quick car analogy, think of it this way. In your old car you only do 40-70mph most of the time. Occasionally you get up to 100+. You get decent gas mileage - about 300 miles to a tank. If you hold the pedal as far down as it will go, you max out at 200mph. Gas mileage drops to about 100-150 miles.

You get a new car and keep the same driving habits. You do 40-70 most of the time, occasionally doing 100+. You get much better gas mileage - about 500 miles to a tank. Holding down the gas pedal, the car does 260, max and gas mileage drops to 300-350.

Coming back to computers, when you're watching HD video, listening to music, surfing the web or writing a term paper, you're only using a fraction of the CPU's potential. Having it clocked down to 1.3 GHz is a good thing and will get you close to the stated battery time. When you fire up a game or start rendering audio/video/3D graphics, the computer will automatically ramp up to the turbo speeds to complete the tasks faster (this is called rushing to idle).

The chip works as hard and as fast as it can to finish the job so it can go back to sleep (reduced power stage). It's very complex, and something better left to the professionals at intel.


macrumors 6502
Jan 16, 2011
Blacksburg, VA
How does it determine when to switch over to the faster speeds? Is there a way to have always be at 2.6GHz?


it will go to 2.6 when it is needed...if you are just browsing the internet it actually may be down at like 800MHz...turbo boost also underclocks...if you are at 100% on all cores, it may boost up to like 1.6...if you are at 100% on 1 will boost all the way up to is to make single threaded apps run faster...and also the turbo boost cuts off around 90-95C to bring the heat down...just let it do its thing..there is nothing you can do about it...except crank up the A/C


macrumors member
Aug 22, 2012
You don't want it to always be at 2.6, that is a waste of battery, power, and will cause unnecessary heat.


macrumors 6502a
Apr 22, 2005
If 1 core is in use and the other is idle, it'll increase the clock speed of the in-use core to 2.6GHz.


macrumors regular
Aug 4, 2005
Gothenburg, Sweden
Turbo Boost works by monitoring CPU and integrated GPU thermals and power consumption. If either of those are deemed too high, the CPU will clock itself down from the maximum turbo bin.

For example, the CPU might stay at 2.6 GHz for the first five minutes of CPU load, but once it reaches a high enough temperature, it will clock itself back down to its base frequency of 1.3 GHz.

Stressing the integrated graphics along with the two CPU cores will increase both temperatures and heat output, increasing the likelyhood that the CPU clocks itself down to the base frequency.

So, the base frequency is the lowest frequency that the CPU will use when being fully loaded. In many cases, especially without any major GPU load, the CPU will probably run at far higher frequencies.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.