W520: How to get full speed and turbo on battery power

Question

Here is how you get around the on battery max frequency limitation (of 1.2 GHz, at least for my i7-2620M) and no turbo (well, almost, read on):
0. Assuming you have max performance enabled everywhere possible (BIOS/PowerManager/Windows Power Scheme)
1. Load ThrottleStop.
2. Set the multiplier manually to your maximum multiplier (e.g., 27x for i7-2620M, 23x for i7-2820QM, etc...) or Turbo (which is the setting after your max multiplier).
3a. Enable ThrottleStop
3b. (optional) Check in CPU-Z and make sure that your highest multiplier is being used when the CPU is utilized. If you selected Turbo, you should have turbo enabled at this point.
4. Disable ThrottleStop
5. Exit ThrottleStop, so that it doesn't waste any battery power, since it is no longer needed
This will change the max frequency (and max multiplier) available from whatever Lenovo decided to arbitrarily fix it at (e.g., 1.2GHz) to the correct max frequency (which in my case is 2.7 GHz / 3.2 GHz for turbo). Now your laptop will be able to correctly go from 800MHz to whatever is the max frequency of your CPU, using both EIST and C1E. Turbo will also kick in, if you enabled it in ThrottleStop and the Lenovo PowerManager app will even show it as enabled.
Thanks Unclewebb for letting us get around this stupid max CPU frequency limitation that Lenovo has imposed on us.
Disclaimer:
Do this at your own risk, since Lenovo does not officially support it.
Turn on active cooling, if you do CPU intensive stuff for any prolonged period of time. This will take away some on battery time, but if battery time is of ultimate concern to you, then this change is probably not for you to begin with.
If you go through prolonged periods of CPU intensive activity, you will lower your battery life and produce a lot of battery heat, because you will have a relatively high discharge rate. A high discharge rate reduces both the number of charge cycles and the maximum charge capacity of a Li-Ion battery. I don't know how safe all of this is, so do this at your own risk and probably monitor temperatures along the way. Other laptops can do Turbo and full speed on battery power (e.g., the slim 3 lb Sony Z, with the i7-2620M), but then other laptops have different designs and cooling systems, so who knows how the Lenovo W520 hardware will react to this.

Answer 1

Hi,
I have the opposite problem - my i7-2720QM is fixed at 2.2GHz no matter how hard I spank 1, 2 or all cores, and no matter what System Performance settings I apply.  It even runs at this speed, and gives the same bench marks when on battery  with the "system performance" set to Low.    
No one even knows what the various System Performance settings actuall mean. E.g. Neither Lenvo support nor these forums could tell me what the difference between "Maximum Turbo","Turbo" or even "Low" under "System Performance" in the Lenovo power manager Advanced settings.
I have been trying go get turbo boost to work for 2 months. I have wasted so much time with this machine, I could have bought 2 Macbook pros for the cost of the time lost.
I dont know why Lenovo have disabled the turbo boost (and the opposite, turbo drop?)  feature for this CPU - is it deliberate, or incompetence?  Its certainly false marketing and extremely annoying that I have to use my ancient PC to do single threaded type work which I know the Laptop can manage if it were not crippled.
So people whos clock speed drops when on battery are the lucky ones.  Mone doesnt even if I want it to.