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bluezone78
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Posts: 11
Registered: ‎09-26-2011
Location: Frankfurt, Germany
Views: 1,528
Message 1 of 5

Thinkpad T420s - is it safe to run the CPU on PM 'Maximum Turbo' mode 24/7?

Hi guys,

 

I have been playing around with Power manager system settings and observed following core frequency behaviour:

 

Maximum Turbo - clocks all cores close to their Turbo Frequency (3.2GHz on mine) and they stay there, regardless if 

                             under load or not

Turbo - frequency jumps between 2.4GHz and 3.2GHz

           - under load jumps to 3.2GHz and stays there (while under load)

 

Balanced - frequency jumps between 2.2GHz and 2.7Ghz

                 - under load jumps to 2.7GHz and stays there (while under load)

 

Low - frequency locked to 800Mhz, regardless if under load or not

 

First, I would like to ask for confirmation if this is really how it should work, and/or if someone is able to observe different behaviour.

Secondly, there is virtually NOTHING in the PM documentation that describes these parameters and what they do!

 

My main question: How safe is it to use the Maximum Turbo mode 24/7?

I can imagine that this CPU was not designed to run on 3.2GHz 24/7 and that the Turbo Boost is expected to occur only ocassionally.

Even if I choose to ignore the heat factor, would this mean increased wear on CPU?

 

Could the 'Turbo' mode be regarded as safe?

After some extensive testing, I can really see performance boost between 'Balanced' (which doesn't use Turbo) and 'Turbo'.

What I don't understand is why 'Turbo' seems to be jumping to Turbo Frequency, when the CPU is idle.

 

I would appreciate any comments and observations.

many thanks

 

//Matt

 

I used HWInfo64 to observe the CPU frequency and Prime95 to generate the load

CPU: Intel Core i7-2620M

jmstuckman
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Posts: 163
Registered: ‎07-02-2011
Location: USA
Views: 1,512
Message 2 of 5

Re: Thinkpad T420s - is it safe to run the CPU on PM 'Maximum Turbo' mode 24/7?

I have the T420s with the Core i5 processor. My observations are similar to yours, except when I'm on the Balanced and Turbo settings, the frequency drops to 800mhz when the CPU is not under load.

 

There is one option you forgot to describe: the "Lenovo Turbo Boost+" option in the power manager. This option appears to lock the fan at a high RPM to cool the CPU more quickly. This would reduce any thermal throttling when running at high clock speeds for a long period of time.

 

Regarding why "Turbo seems to be jumping to Turbo Frequency when the CPU is idle", please note that your CPU is never completely idle. WIndows and its applications run many processes and tasks in the background, and it is normal to see a burst of CPU activity every couple of seconds. To observe this, download the "Sysinternals process monitor" utility and watch all of the background activity that occurs.

 

Regarding the increased wear on CPU, running at high temperatures reduces the lifetime of electronic components. There are no problems other than the "heat factor", but excessive heat can be a significant problem.

CorkyG
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Posts: 421
Registered: ‎08-13-2010
Location: Tucson, Arizona
Views: 1,466
Message 3 of 5

Re: Thinkpad T420s - is it safe to run the CPU on PM 'Maximum Turbo' mode 24/7?

As for running 24/7, laptops are not really designed for that. It should be OK, however, if it is on a good hard surface and you do not close the lid. Some of the air for cooling comes through the keyboard area, so it is best to leave that open.
lead_org Microsoft MVP Contributor
Microsoft MVP Contributor
Posts: 21,009
Registered: ‎12-19-2008
Location: Australia, Melbourne
Views: 1,456
Message 4 of 5

Re: Thinkpad T420s - is it safe to run the CPU on PM 'Maximum Turbo' mode 24/7?

it is okay as long as the temperature is kept under control. But these mobile CPU arent like the Xeon and Itanium CPU where they are designed to run at max performance for their expected service life.
Regards,

Jin Li

May this year, be the year of 'DO'!

I am a volunteer, and not a paid staff of Lenovo or Microsoft
bluezone78
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Posts: 11
Registered: ‎09-26-2011
Location: Frankfurt, Germany
Views: 1,436
Message 5 of 5

Re: Thinkpad T420s - is it safe to run the CPU on PM 'Maximum Turbo' mode 24/7?

jmstuckman: thanks for your reply, the reason why I didn't mention the 'Lenovo Turbo Boost+', ecause it is not visible in the 'Advanced' mode. Why there is no equivalent for it in Advanced mode is beyond me.

I think I will stick with 'Turbo' mode, for the time being.

//Matt

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