Windows 7: Performance decrease while on battery

Hi,

I have a Dell Precision M4500 and Windows 7 professional (64 bit).

If the power supply is plugged in my notebook runs at full speed as long as the power management is set to highest perfomance. However if I unplug the power supply the performance decreases no matter what kind of power management I select. Even if I generate a custom power management with everything set on 100% the performance is worse.
Is there any other power mangement option besides the power management in system controls (I couldn't find anything in BIOS)?
How do I get the highest performance of my notebook when no power supply is plugged in?


Thanks.

Hello ekjb and welcome to Seven Forums.

How old is your battery? It's possible that it's useful life expectancy and performance have been compromised due to age. Even if you just bought it, it could have been sitting on a shelf somewhere exposed to temperature extremes, etc.

You could also go through this tutorial for basic and advanced power plan settings to see if you might have missed something.

Power Plan Settings - Change

You could also try running a Power Efficiency Diagnostic Report to see if there are any reported errors, warnings, etc.

Power Efficiency Diagnostics Report

In the bios you should have a Intel SpeedStep & a Intel TurboBoost setting under performance. What are these set to ?
Also do you use the Dell Control Point System Manager ? as this also has a Power Scheme and Sleep Mode setting.
And lastly did you install the Turbo Boost driver ? Intel Turbo boost driver (Dell)

Hope this helps a bit

With laptop they try to save as much power possible when on battery. I would first look at whats running in the system try and disable all things not needed with using MSCONFIG the only things you really need in the try is sound, battery, and antivirus program. Since its a Dell im betting it has a lot of programs running on boot, clean these up and see how the machine works..

Many PC's have different CPU speeds, depending on activity, battery, etc. It sounds like your system is "throttling back" when on battery (to conserve battery). I have a new Lenovo Ideapad with an i5 CPU and it will do this.

Thanks for the replies.

Maybe I should first emphasize that the performance of my notebook with power supply plugged in is absolutely fine.
What I want is that it has exact the same performance if it runs on battery.
Consequently I do not think that the problem relies on bios settings or things like that unless there is a distinction between battery and power supply. However I checked the bios settings and SpeedStep and Turboboost is enabled.
I do not use Dell Control Point System Manager. Maybe I should use it?

I checked again the Power plan settings but couldn't find anything uncommon.

Since the machine runs perfectly on power supply I do not think that applications running in the background could be a problem.

Any other ideas? Is it maybe possible to switch off the entire power management stuff?

With SpeedStep, when the notebook is connected to the Power outlet, most apps and the Internet etc. run with speed almost the same as a desktop.
When using a battery, the processor drops to a lower frequency (by changing the bus ratios) and voltage, conserving battery life while maintaining a high level of performance.
When SpeedStep is enabled, the computer does not run at full speed until the faster speed is needed. This reduces power consumption and increases battery life.

You might also want to have a look at the advanced settings under power options

I have a Fujitsu Celsius H910 Windows 7 professional (64 bit) and have the same problem. Tried to turn off speedstep in BIOS but there was no noticeable difference when on battery, just a bit slower when plugged in (no turbo boost when speedstep disabled?). I have been doing tests with Solidworks benchmark and Solidworks mostly uses only one thread.

Edit: CPU performance on battery is only 25-30% of CPU performance when plugged in.