[Samsung Epic 4G Touch] igorb81:
Is your phone getting hot? I suspect you possibly have a media bug it seems to be very common on ICS and JB. Use an app such as SystemPanel to see your live CPU usage. Once installed under settings check App CPU monitors, show app CPU time, Show app status, System monitor, system processes < the most important. I have a paid app so I am not sure how much you will be able to do with a lite version. You may be able to do all this. I needed monitoring ability so I bought it in the past to track down issues with my phone not sleeping on ICS AOKP back in the day.

After all of these are checked you can see on the graphs and pie charts in the main screen of the app your memory usage, CPU, storage, CPU clock etc. Look at any processes that may be eating up your CPU usage, slowly scroll down and look on the left side the little bar graph next to each process will show current CPU usage. Let it sit and observe your CPU usage by processes. If you see media process using up most of your CPU you have a bug.

Here is the screenshot of the app:

To fix it I disabled all of the useless processes from starting up automatically every time the phone is booted with Autostarts app. Specifically media storage. Let media storage run during startup but DISABLE it after Startup. You would click on After Startup section and disable any useless services. I disable a lot since I don't want a lot of apps running in the background all the time syncing useless stuff to me or just eating up resources for no reason. I have over 300 apps. I don't need all of them running all the time. Some apps I only use once in a while and there is no reason for them to hog up the resources. Once you disable them you will see them crossed off in the list and they will not be running in background

I tried to make this as detailed as possible. Doing this will really optimize your phone. I have zero problems with my phone right now. You have to disable processes based on your needs. Don't go too crazy by disabling everything. Obviously some things need to be running to have a fully functioning phone. I hope this helps someone complaining about their phones running hot and dying rapidly. It happened to me initially.

As I said many times I am getting excellent battery life with full functionality (minus sending MMS which I don't use) I get over 20 hours and over 3 hours screen time with moderate use on 1500mah battery. I do have my phone underclocked to 1ghz and undervolted to -25mV Also I have a screen off profile set in SetCPU app to min and max 200mhz while screen is off if something tries to go nuts while the screen is off it will be limited to 200mhz. My phone deep sleeps all the time when the screen is off. This is the key to great battery life. I also use CPUSleeper not sure if it helps but I thought it wouldn't hurt. I don't need my emails pushed to me every second and any other useless stuff synced every minute. I set my own sync schedules for everything. I am at my office desk most of the day and don't need my emails pushed to me every second.

Also, I use ROM toolbox and changed build.prop to 190 dpi! What a difference did that make!? Thank God I am not blind. Seems to me that Samsung had the blind folks in mind when they optimized the phone to 240 dpi. It just looks gross. I changed it back to 240 yesterday temporarily just to see how it looks and it made me sick. I couldn't stand it for 30 seconds. I like everything nice and small. Doing so a lot more stuff fits on the screen like it should at 4.5"

I am not responsible if you screw up your phone. Be careful! If you have rooted and flashing ROMs you already assumed all responsibility for your actions. I just shared some of the tweaks that I have learned over the years. If you find it helpful hit the thank button and enjoy your phone like I do. :)