I am a big fan of the overclocking wiki page. Even if you choose to keep the stock kernel, there is some good info on how you might keep the N900 in a low power mode: ignoring nice processes and declaring everything you can as a nice process, for example

I know there is a way to do the following, but I don't know what it is. Why can't I underclock and undervoltage everything on the phone when I am not using it -- when the screen isn't on, and then put it to some other setting when the N900 is in use. Can the N900 detect when I'm overwhelming a EDGE network and bump me up to 3G, and then drop back down to EDGE when the network traffic slows down?

What else can we declare as a background process? I would like to make everything possible a background process, but there are a few holdouts: modest, the address book, updating contacts, none of these really need to be processed in real time, but seem to slow down my device whenever a new network connection is established.

I think about it. But it was discovered that for specific application there is no advantage because it looks like N900 on high frequency uses less energy per CPU clock.

So, underclocking may help only if you have some application which eats CPU without any useful finite work - any useful finite work requires approximately the same number of clocks in any frequency.

And yes, there are some another very specific scenarios then underclocking may save battery even more energy expensive CPU clock.

EDIT: modest can be set into background, I tested it. Moreover, almost any application can have nice 1 priority - that actually has a VERY small difference with normal priority.

"Can the N900 detect when I'm overwhelming a EDGE network and bump me up to 3G, and then drop back down to EDGE when the network traffic slows down?"

it has no sense - measurement shows it uses the same energy amount. 3G was designed for low power device in mind. I can't give you a reference for a moment but somebody did a measurement.

ego shin that's odd you say that.

i overclocked mine to 125mhz-750mhz similar to titan's ulv settings,

and with only 2g, I was draining 1 percent an hour idle

i was out in the car stopped waiting for someone so I enable dual/3g and I go straight for youtube for some quick entertainment.. that was at like 7pm, then I left it on 3g, and by the looks of my battery graph, the battery drained so much faster, and by morning it was dead. so i think it's clear that 3g uses more energy (at least in regards to the n900 specifically)


i'll post some screens of my batter graph

its not conclusive evidence because of all the other factors involved.. but its somethin

The power consumption of 2G and 3G is linked to the quality of your coverage. If you are in a good coverage zone you'll see that your battery won't drain as fast. It's the same for every phone.

But anyway according to the specs of the N900 the battery life on 3G is not as good as on 2G, but that is also common to all the phone I've seen so far.

I experienced nothing different between 2G and 3G on my device. Both draining about the same power. 2G doesn't saved anything for me but 3G does. Lol i'm the only odd one I hope.

3g uses more than double power of 2g for me. Except when idle, power consumption is low enough for both in that case.

In the case of streaming audio, 2g uses about half of 3g. 128kbit/ shoutcast stream.

In the case of downloading stuff, 3g uses alot less per byte transfered. I tend to switch to eg for downloading few hundred megs with gpodder, and switch back to 2g after that.

In the case of lots of IM/IRC, 3g uses about 5 times more power than 2g for me. 3g is really bad at low-rate but frequent transmission.

And as always, it depends on your network's configuration. Signal power plays a role, but for the lowrate frequent transfers the network settings have much bigger impact.

I think you'd be right if every frequency used the same voltage. The overclocking wikipage states that the power consumption varies linearly with the frequency, but quadratically with the voltage, so I can see a power savings when I am running slower with a lower voltage.

Regarding Modest: I would like it to be nice, except when I bring up the GUI. I am not sure how to do this.

You may use a different tower for 3G which is located far away.

It's not just about eadiated transmission power...

In my experience it restarts each time then it comes to GUI mode. So, it loses "renice" value and returns to normal during GUI.

But anyway, "renice -1" is actually very slight difference with normal priority. It is very difficult to note about it.