Reduced Processor Performance on Battery?

Hello all,

I recently purchased an HP Tx1220. When playing an HD movie (720p), I have flawless playback when the AC Power is connected; However, when I'm running on battery, the video won't playback (audio plays, but video shows just a few frames every few seconds).

I have tried changing all of the Vista Power Settings to be identical for Battery Power and Plugged In settings, but I still have the problem. I have also tried changing a bios setting which I believe was called Battery Performance (changed it from Battery Saver to High Performance) without any luck.

Truthfully, I probably will never find myself in a situation where I will want/need a high level of CPU performance when using the battery; However, I was quite surprised to find this diminished processor performance even after changing the settings I mentioned. It appears to me to be a hardware issue.

I guess my main question is whether this is typical of other laptops or if this is just an HP issue? Would I get diminished playback performance of HD footage running on batteries on other lightweight (12'' machines)?

This is my first laptop so thanks to anyone who can clear this up for me.

Josh

 

I think this is because of ''Intel Speed step'' which automatically underclocks ur CPU when it is not used or on battery power to preserve battery life.

You can try using a programe called ''Notebook Hardware Control'' Where you can 'force' the CPU to run on full speed!

 

Thanks for the response.

Actually, the processor is an AMD Turion, but after looking into it, AMD has there own version of Speed Step called "PowerNow!". I guess this could be the source of the problem.

Can anyone verify that this is a common thing to occur amongst all laptops?

 

Yes, if your cpu is constantly in the low power state then there will be some lag. What power profile are you using when on battery power? I notice lag when I set it to 'Power Saver' profile since the processor is constantly at 800MHz. But with 'Balanced' setting there should be no lag when playing HD videos while on battery.

If you are using the stock HP installed Vista then go through the active power profile set the cpu max frequency to be 100%. This will ensure that the processor will increase to the max frequency while on battery as and when necessary.

 

I can verify. It does the same thing to my tx1120us. Early BIOS has Battery settings for Battery Saver or Performance but it never worked right. The latest BIOS has this fix. Set to "Performance" in BIOS. Set CPU to 100% in Advanced Power Settings under Battery power. You should see significant improvement but it will never been 100% stutter free and it will drain the battery very fast.

To monitor CPU clock, download AMD Power Monitor from http://www.amd.com/us-en/Processors/TechnicalResources/0,,30_182_871_14098,00.html.

In most cases, I would rather connect to A/C since the battery will most likely not outlast a two hour movie.

Are you watching movies from DVD or Media Center Edition via USB HDTV tuner? In my case, I use MCE to watch and record HDTV using Fusion USB HDTV tuner. Using old BIOS, it was stuttering like crazy and new BIOS helped reduce stuttering.

Peter

 

Thanks for the info Peter.
I updated the BIOS, and now when I change the Battery Setup to High Performance, I can playback the video.

 

yup thats the fix, go to bios to change the setting, or actually update it first just like what you did.

 

PowerNow! should work in such a way that if CPU is demanded it will step up and step down when it is not needed. it sounds like yours was somehow locked into a stepped down mode.