In order to make our phones conserve battery, the CPU frequency is reduced when the screen is off. I am not sure if this happens with 100% stock, but it is certainly the case with custom ROMs (e.g. I'm now running Eclipse 1.2), and I know some of the performance scripts do this as well.
Ordinarily, this is great, because it drastically improves battery life. But there are times when I want a background process to run (e.g. app updates or internet downloads), and I want to turn off the screen to save battery, but I would like the process to keep running at full speed.
Yesterday, I was transferring files over wifi, and I was getting speeds of 1.2MB/s or more when the screen was on, but when I turned it off, the speed dropped to around 400KB/s or so. I turned the screen back on to check, and sure enough the speed resumed at the higher rate. (BTW, I have the wifi sleep policy set to never). I'm assuming this was all due to CPU frequency throttling.
Ideally, I would like to have the current battery-conservative behavior most of the time, but in some occasions I would like to switch the behavior to allow full CPU speed during screen-off.
Is there a setting I can change (or a script, app etc). I've seen some info about SetCPU. Does anyone recommend this app, and is it likely to conflict with or be overridden by the settings in a custom ROM or performance script such as supercharger etc?
I would love it if someone could point me to some more information about this issue, and the Android settings and hacks that affect it. Thanks in advance!