Just did a couple of tests on my unrooted Galaxy S2 i9100 running ICS 4.0.4. You see, I'm using Juice Defender Ultimate and I've noticed it enhance my battery life. But the problem is Apps cannot underclock the CPU without root access. I was scrolling around the Galaxy S2 settings and it occurred to me that two options for power saving is present. "System Power saving" and "Custom Power saving". At first galance I thought the "Custom" mode is the same as System Power Saving option but gives the ability to change how power saving is done... IT IS NOT!!! Both are two different systems and can function simultaneously!! Shockingly when I clicked "System Power Saving" option a notice appearing saying "Attention, System power saving activated, performance restricted!" really is it? Quadrant Standard shows With power saving : 2645 Without Power saving : 3175 Solution to save tons of battery is! Turn on "System power saving" (Settings -> Power Saving) while using Battery saving software. And save loads of power no questions asked as it covers a drain area which no app can do without root. NOTICE : Don't enable "Custom Power saving while other Battery Saving apps are running!!!!"