Also, consider the fact that overclocking lower limit (i.e. setting 500-900) result in power savings during standby - as N900 finish it's "idle tasks" quicker, sitting in 0mhz longer every second (as compared to switching into 125 or 250 mhz lower limit while idle - see batterypatch or other voodoo that actually use power to monitor dbus events (idle, locked etc)

/Estel