On WM2003se i noticed many programs can reduce battery life, becaue they use ram to run and ram uses battery. The brighter something is, the more energy it uses. So a brighter backlight should use more battery. On wm2005 the backlight is the same, but i dont know how open programs affect battery life on that os.

 

hi, do u think 1 or 2 mbs of ram really use a noticable amount of battery power?

... I don't mean backlight brightness, I mean color brightness like shade, white vs. black

If background programs put load on the CPU or access hardware resources e.g. storage cards or BT/WiFi radios then a higher power consumption will result. Example: playing music in the background while word-processing. If the background programs are indeed idle then I would not expect any practical differences in battery life. Starting and closing programs many times can use more power than leaving them alive. I cannot follow the RAM argument. Surely the PDA cannot distinguish between memory addresses in use and not in use.

Transcendental x50v: 4 + 8 GB SD and CF Transcend cards

Well, the colors aren't going to make any real difference consumption-wise; whether the display is black or white won't matter, since it's the backlight which consumes the bulk of the display's power allocation; it's a bit like worrying about whether you should worry about whether a car which is painted red will be more fuel-efficient than a car which is painted blue; it's the engine inside and the speed which runs the car at which causes your car to go through gas. While the 'paint' in this case takes up a bit of power, it's still probably less power than is used by the CPU in an 'idle' state.

As far as programs running is concerned - yes, you'll probably lose some power if you've got programs running in the background, if the programs are taking up CPU time in order to refresh something, to autosave a file, or what have you - if it's checking the network or playing an MP3, expect more power to be used. And one more thing to note - it doesn't matter if you've got 30MB of RAM in use or just 2MB in use, as far as the power usage is concerned, since it's all running off the same bus and the CPU'll have to take time to update and maintain it all, even if most of the RAM is 'available' and not allocated to some program or another.

WM5's advantage is that data is kept in persistent memory, while program state information and the like is kept in the powered RAM; the reason it extends the 'battery life' is because you don't have to worry about allocating so much battery power to keeping the contents of main memory alive, thus letting you push closer to the edge as it were - when the battery is drained, your data remains intact.