Brad Wardell's site for talking about the customization of Windows.

My Microsoft Surface is a constant companion.  It is absolutely central to my workflow.

One of the challenges I’ve had with it is battery life.  There’s a lot of things you can do to help with your battery life but one simple thing I’ve done, for now, is to set the max CPU when on battery to 99%. 

Setting the max CPU to 99% prevents the CPU from going into Turbo mode.  For me, this accomplishes two things:

(1) I get roughly an extra hour of battery out of the system

(2) I don’t get the annoying fan when I watch videos


Set your maximum CPU while on battery to 99%

Here’s how it works:

Step 1: Download and run 


Step 2:  Go to advanced power settings and go to the new option: Processor Power management


Set the on battery to 99%.


There is no step 3. 

You should notice the behavior difference fairly quickly on battery.  For one thing, when you have Edge running on an ad intensive site or are watching a video your CPU speed will not go nearly as high (on the other hand, it won’t get power throttled to 0.5Ghz either which is a big benefit).



Hope this helps.  Feel free to comment if you have questions. 

on Jan 14, 2016

Great tweak!  Do you think this would apply to the Surface Pro 3?

on Jan 14, 2016

Wow, I was just wondering the same thing... Would this work on my Surface Pro 3???

on Jan 14, 2016


on Jan 14, 2016

Adding an hour with such a simple tweak is pretty damn clever, Brad.  May I ask what the pre-tweak baseline SP4 battery life was day-to-day?


on Jan 15, 2016


Adding an hour with such a simple tweak is pretty damn clever, Brad. May I ask what the pre-tweak baseline SP4 battery life was day-to-day?

An hour less ....  [But I'm just guessing]...

on Jan 16, 2016

You sure you're just guessing?

on Jan 17, 2016

it was about 5.5 hours. mow its 6.5 hours.

if i set it tp 33% i can get 10 hours but i notice the perf hit.

on Jan 17, 2016

Thanks!  That's about 3.5 hours more than my current laptop, so SP4 likely to happen soon.

on Jan 23, 2016

Well after trying this tweak for my SP3, I can definitely see the improvement in battery life, but more importantly, the fan barely turns on now when doing light tasks.  It really is a night/day difference.

on Jan 23, 2016

Works great on my SP4. I like the fact that it keeps the fans off during video runs.

on Jan 27, 2016

Hi, If this is addressed in a future Microsoft update is it possible to remove this tweak?



on Feb 04, 2016

Hi, Works Great in my SP4. but I want to know, how to disable it(In particular SP4 MAX_Processor_State )
actually if microsoft  solve this problem by update, These settings are problematic to update?

Thanks a lot

on Feb 11, 2016

If you don't want to loose 1% of your CPU capacity you can use Real Temp and disable the Turbo mode


BTW is the Surface Pro 4 reliable? I read too many awful comments about the unresponsiveness of the screen. I'm hesitating between the SP4 and a VAIO X Canvas for for my artistic work. I need a modular system that can replace a graphic tablet.

on Feb 11, 2016

Quick question: Why does this need a tweak? I thought you could set the power settings like that anyway in Windows . Is it disabled in the SP4?