control over Intel Turbo Boost technology ?

[idata]

Hi,

I intend to purchase a notebook having the new Core I5 processor on board and before making an order I need to choose amoung 3 frequency configs for the i5 processor (2.16-2.4GHz with different overboost options, +-100Euros)

At http://www.intel.com/support/processors/sb/CS-029908.htm http://www.intel.com/support/processors/sb/CS-029908.htm there is written:

How is Intel® Turbo Boost Technology enabled or disabled? 

Intel® Turbo Boost Technology is usually enabled by default by a switch in the bios where you can either enable or disable operation. Other than this, there are no user controllable settings to change Intel® Turbo Boost Technology operation either in the hardware settings or operating system. Once enabled, Intel® Turbo Boost Technology works automatically under operating system control.

I'm not an expert in that domain and I found this explainaition a bit confusing. Is the turbo boost mechanism enabled just by writing into some kind of processor control register (done by the BIOS at boot) and then the mechanism is working autonomously just using processor internal H/W resources ?

Or is there still some intervention of OS (Windows7, linux) needed to make the mechanism efficcient ? What exacty is meant by "operating system control" at the end of the explaination from Intel ?

Thanks in advance for your time!

Cheers,

Thomas

[idata]

Basically, if your motherboard's BIOS has this option, (not all do) you can choose to either enable or disable the turbo boost technology. If you choose to enable it, the system will manage how fast the processor will go according to heat, energy consumption, and demand. when a program requests more performance, and the CPU is under it's specified limits, then it will clock itself up accordingly. it's somewhat similar to speedstep, in a few respects. but in reverse, as it's clocking the CPU up and not down.

Basically, yes it is run in the background and you cannot control it. you can boot with it on or off, and while it is on, it is under system control only.

[idata]

Thanks for your reply!

So my conclusion is: S/W (i.e. BIOS) just enables Turbo Boost at boot. Then Turbo Boost works autonomously (processor internal H/W) and no more S/W intervention (BIOS, Windows, Linux) is needed to make the Turbo Boost work efficiently after boot.

Please let me know if my conclusion is wrong.

Cheers,

Thomas

[idata]

that's pretty much how it works.

basically you enable it in the bios. (s/w) then after you have boot the system up and it is running, you execute a program. that program then may reqest more performance (such as a game) from the OS (P0 state) and the OS then sends this to the CPU. the CPU will then check and see if it is under set thermal and power consumption limits, and how many cores are active,(h/w and microcode) and then speed up the CPU accordingly to attempt to meet the OS and program demand if below these limits.

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

• Number of active cores
• Estimated current consumption
• Estimated power consumption
• Processor temperature

[idata]

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