Increasing the Battery Life of an HP DM3

Hi guys.

I am interested in increasing the battery life of my HP DM3z.

I love this little laptop, it is more than powerful enough for my needs, it's tiny, it looks great, and it cost only $500. The only thing that I wish it had was a little bit better battery life. I typically only get 4-4.5 hours of battery life with 30% screen brightness, Wifi on, and doing your typical web browsing, etc.

I already undervolted the processor to stable conditions.

I am looking to get into the 5-6 hour range, and was wondering if there was a way to either:

1. Underclock the AMD Neo Dual Core L335 processor

2. Disable a core of the AMD Neo Dual Core L335 processor

3. Underclock the ATI Radeon 3200 HD Graphics

4. Some other way to increase battery life??? (Install a different operating system, or something?)

I really wish HP had a 9-cell battery option for the DM3... Any info would be appreciated. Thanks guys.

 

- load soffware to monitor power use and battery life: batterybar, battstat.
- add RAM to reduce stress on the HDD OR put HDD in standby after 1 min of no use or get a low power Samsung SSD
- Set power saving profile to switch off aero to not use 3D acceleration
- disconnect all USB devices and bluetooth

 

Thanks for the help thus far. I already never use Aero as I prefer the classic layout.

 

- Install Flasblock in Firefox
- Change the 7200rpm HDD to a power efficient SSD or 5400rpm.
- Windows XP usually gives better batterylife than Win7, but not always.

I would advice against installing Batterybar as it has caused problems on several of my laptops, even after removing it.

 

Doesn't W7 have a conservative mode? Anyway, you can only cut back so much before it becomes impractical. Why don't you just buy an extended battery?

 

Underclocking makes less difference than changing the voltage, once you hit the minimum voltage I wouldn't bother with underclocking. Just disable the other core, chances are that on the lowest multiplier you'll be getting something like 800mhz, with only one core I really wouldn't make it any slower otherwise things will start to crap over and mess up.

The reason it would be better to keep the voltage and disable one core instead of underclock both and not disable one core is because then you'd be running them on a much higher voltage than is needed, plus some programs still don't make proper use of multi threading.

If you're carefull and know what you're doing, it's possible to modify the graphics drivers to use a lower voltage. Again, voltages make a much bigger difference in terms of power consumption than clock speeds, it's just a lot more critical that you get it right here since the drivers are loaded at startup. If you fluff up then you have to boot into safe mode and change the driver back to what it was and start over again.

The first thing you should do is just use the screen on minimum brightness though, also make sure you have the wifi set to power saving settings (you can usually adjust the transmit power and things like that through device manager), that might buy you another 15 minutes.

 

Really?? Anyway, you are correct about the screen brightness. That's the biggest drain on power by far--and easiest to correct.

 

How do you disable a core? And how much more battery life would having a 5400 RPM Hard Drive have over a 7200 RPM Hard Drive?

 

It can make a 2 watt difference when the hard drive is used. When it's idle the difference is smaller.
Charts, benchmarks 2009 2.5? Mobile Hard Drive Charts, Streaming Read Operations

If the total power consumption is 20 watt, 2 watt would mean 10% difference. RM Clock can tell you the total power consumption.

 

You can disable usb ports if they're not used. It'll save you a bit of battery life.

 

To get to the wifi settings:

1. type "device manager" in the windows menu
2. right click and run it as administrator
3. find your wireless adapter
4. right click on it and select "properties"
5. under one of the tabs you should find the power management, most intel cards have it, I'm not too sure about other makes though

Disabling a core is pretty easy, here's how:

1. find "msconfig" on the start menu (just type it in)
2. go to the "boot" tab
3. then click the "advanced options" menu
4. there is a click box, normally this is left un-checked but if you enable it, it will let you set the number of cores used at boot, leave all other boxes as they were (I guess you could tell it to use less RAM if it's barely using what it has, if you're just web browsing I doubt you'd use all your 4 gigs, however this is not something you can change on the fly so if you ever wanted to do something more demanding you'd have to change it and then reboot otherwise you'd be stuck with 2 gigs or whatever you set it to, I doubt you'd get more than a few minutes out of it anyway).

I you're don't use the optical drive then you can disable that through device manager too, just disable the driver and it will basically turn it off. I think you have to reboot for it to take effect though. Probably won't save mch energy though if it isn't being used.

 

First of all, that doesn't actually disable a core, it's just a debugging feature that only applies during bootup.

Second, modern dual-core CPUs are not designed for you to disable a core - it's far more effective to undervolt the CPU, if you like, or just run it on minimum power mode (locked to a lower clock speed). I'd recommend the latter, from my experience, tweaking that stuff doesn't help all too much.

Disabling USB ports and the ODD will barely make a dent, but I suppose something is better than nothing. Replacing the HDD with an SSD would be expensive, but it would reduce power usage noticeably.

 

Agreed.. undervolting CPU saves more money... but IMO , ur not going to save anything that much by getting a SSD instead of HDD.. and even disabling ODD or wifi... try undervolting first...

 

How do you lock it to a slower clock speed?

 

Selecting Power Saver profile should already do that.

To make sure you can do it with RMClock.

 

None! Tests reveal no significant difference. Therefore, just buy the faster more efficient drive.

 

From those charts, a fraction of a watt seems a more typical difference. (Be sure not to count the 1.8" drives.)

Also, since the 5400 rpm drive is generally slower, it will spend more of its time being accessed (which uses more power), and less time idle. And you will spend more time idle... some of your extra seconds of battery life will be spent waiting for things to load.

 

His current hard drive is a WD3200bekt. He can gain about 10% battery life by upgrading to an Intel SSD according to these tests:



More recent SSDs can have better battery life than the Intel G1.

 

With his computer ussage patterns, 5400rpm drive will spend the same amount of time as a 7200rpm drive accessing data. loading a webpage from cache will will not use the hdd for "extra seconds" because 5400rpm and 7200rpm drive will be done in a fraction of drive. Most likely, 7200rpm will take longer to spin up, and overall, 7200rpm drive will probably spend more time spinning up and accessing data while drive will go to standby mode faster.

Also, consider using a program called eboostr. Insert a memory card into your dm3. Use both your ram and flash memory to cache your programs and internet browsers. Put the temporary storage file for your web browser on a flash storage. Since flash storage such as sd card consume significantly less power than a hdd, you'll save a fair amount of power.
For me, the hdd is mostly spinned down when using eboostr. So i get an extra 30min-1hour run time on my acer aspire one netbook.