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

Question

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
Solved!
Go to Solution.

Answer 1

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.