Power Consumption: HD or Optical Drive Uses More?

Does anyone know which device uses more battery power, the hard drive or optical? I ask I want to play movies when traveling and wondered whether I should play movies from the DVD or copy them to my hard drive for playback. Any thoughts??

 

Hard drive can get the job done quicker and more efficiently.

Optical drives are slow and will just draw more. You will get more battery life watching from the HD than the dvd drive

 

A simple test by watching power consumption while running on battery suggests the optical drive uses around 3W when running at full speed. Hard disks are typically 1W when idle and 2 to 2.5W read/ write.

Vista stretches the DVD playback time compared with XP by using RAM as a cache and only reads the disk for about 1 minute in 10. However, another factor is that while you can set the hard disk power-down timeout as low as 1 minute, in my experience the background processes tend to keep the hard disk awake. I've occasionally heard it power down then immediately restart.

John

 

Hey John, thanks for the details, just what I was looking for. So if I understand you correctly, and generally speaking, even though the HD uses less energy, I would be better off playing a movie from the optical drive since Vista only reads the disk 1 minute in 10. Is this correct?

 

It would depend on whether you could get the HDD to power down and stay off. If the HDD continues to spin then you might as well use it.

And if the HDD does power down then reading a flash drive or media card is likely to take less power than the optical drive. I was trying to make the point that Vista's use of RAM as cache can give 10% to 20% more playing time. What I don't know is whether than caching would also apply to playback from the hard disk.

The only way to be really sure what works best for you is to do some power drain tests for different options. Start up the playback, pull out the mains plug, set the display to a brightness you are comfortable with, turn off the wireless, etc. Then wait a few minutes for the power drain to stabilise and look at the battery gauge to see the % charge and estimated run time. Write down the clock time, % charge and estimated time remaining. Make more observations about every 10 minutes for an hour or so. Then you can estimate the total run time from the drop in the battery charge for the period of the test.

I use the battery info page of RMClock to give me the battery capacity, charge level and power drain so I can check that Window's numbers make sense.

John

 

Ok, I'll look for the RMClock info page. Thanks again.

 

Ive always found it more efficient watching from the HD or a USB stick.

When i watch movies on the train, i notice it going down quicker when watching dvd discs

 

Most dvd drives take 5v of power at around 1amp, so 5 watts. Harddrives usually take around 2-3 watts of power, so you should get slightly more battery life from using the internal harddrive.
However you can get more battery life if you consider undervolting, it will help decrease the power used by your processor yielding longer battery life.

Their is a guide here on nbr, flipfire made it
http://forum.notebookreview.com/showthread.php?t=235824

K-TRON

 

what about watching from an external hard drive like a western digital passport - which is powered by the usb itself? how power hungry is this option compared to the HD and the DVD drive?

 

External 2.5" HDD uses the same power as internal 2.5" HDD (subject to differences between products) plus a small overhead for the USB interface board. SD card or USB flash drive are other options which won't use much power.

John

 

Use a USB flash drive, its alot better than the optical drive. Less power consumption/noise