# core i5 / i7 powermanagement turbo mode....

## temnozor

Is there any HOWTO available to make it working?

Using win7 i don't even need external tools to make my core i5 750 scaling with voltage and frequency that is set in bios options

Now i want to try to get a working powermanagement running my gentoo installation.

On default bios frequency settings the turbo mode of core i5 isn't active and it does not clock to more than 2.66hz

my kernel config according powermanagement->cpu frequency are

http://666kb.com/i/bo0hgagbwd9w8dsym.jpg

```

watch grep \"cpu MHz\" /proc/cpuinfo

```

shows me that the cpu clocks with 1.2ghz (idle) up to 2.66ghz(load and no differences between load on one core or load on multiple cores)

it should clock up to 3.2Ghz

i tried different kernel settings (CPUfreq governor...deprecated intel speedstep...) but couldn't manage something else than powermanagement between 1.2Ghz-2.66Ghz or no powermanagement and running "full speed" (2.66Ghz or what i set in Bios) all the time

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## EatMeerkats

It is probably already working, as long as you have acpi-cpufreq and the right governor installed.  /proc/cpuinfo will never show anything higher than 2.66 GHz — try downloading and compiling http://www.kernel.org/pub/linux/kernel/people/lenb/acpi/utils/pmtools-latest/turbostat/turbostat.c and you should be able to see the turbo boost working.

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## rh1

You can also take a look at i7z. http://code.google.com/p/i7z/

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## temnozor

ok i tried both (thx for the links) and it looks like the turbo mode is working

but there is something strange....

both tools show me:

the cores are always almost equally clocked

there is no e.g. core0 and core1 on 1.2Ghz while core3 is on 2.66 or 2.8 Ghz...

either it is a bug of getting the clock values or there is something wrong

they are swapping between C0 C1 C3 and C6 powerstate

maybe is it an issue of sheduler swapping processes between all cores and causing an equal average clock for measuring interval?

edith: but that can't be because running nbench shows me 100% in powerstate C0 of one core while the others are altering between powerstate C1 and C6

and all cores are shown with same clock

is there a way to check the voltage of the cpu to make sure its adjusted with altering the clocks in powerstates?

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## s4e8

Yes, all active cores have same freq. The speedstep interface report 4 cores have indepent P-state, but real freq is not.

The real freq is:

C3/C6 state: inactive, no freq at all

C1E: always lowest freq, aka 1.2G

C1/C0: the higest speedstep-ed freq amongst activte cores, if the freq is higher than rated freq (aka, 2.66G), then active turbo boost depend on current power/temperature condition.

If you disable cpufreq, the C-states still avaible. 

If the C1E is enabled, you got: 0 (C3/C6), 1.2G(C1E), 2.6-3.2G(C0).

If the C1E is disabled, you got: 0 (C3/C6), 2.6-3.2G(C0/C1)

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