[HTC Amaze 4G] KnowledgeBroker:
There are several other things you can do which may be more effective than what you are trying to do- or even more effective WITH what you are trying to do.

First, don't lower the minimum clock speed, 384 is the minimum that HTC chose, probably for multiple reasons. As long as your phone is going into deep sleep, it doesn't use ANY processor, and on any governor EXCEPT battery saver, it is VERY rarely idling at the minimum speed.

Next, look at the init.post_boot.sh and init.qcom.post_boot.sh files(you may have one, or you may have both, faux added the second one in later builds) in the system/etc folder, that sets many of the kernel settings. Do some research into how changing the line for "down_differential"(which is 5 stock, 1 increases battery A LOT, but increases lag a bit too), , "up_threshold"(stock is 90, setting to 95 increases battery, but takes longer to get to full clock speed), "sampling_down_factor"(stock is 4, you can lower to 1 for increased battery life, and slightly more lag), "sampling_rate"(latest faux changes to 30000, setting to 50000 means it checks whether to increase/decrease cpu speed less often, and gives better battery life).. changing those values will have much bigger impact on battery life, while adding a little bit of lag at most if you change them quite a bit. Also, look to see if you have a line that says "echo 1 > /sys/devices/system/cpu/cpu1/online", if you do, change it to a 0, 1 forces the second core on ALL the time instead of letting ICS decide when to turn it on.

Next, look at thermald.conf in the same folder, some of the biggest differences in battery life between roms is because of that file- faux replaces it with his later kernels, but I'm not sure if it is to increase battery life, or increase performance. His is definitely different than any rom I have seen, and people report much improved battery, and that file is likely why.

Doing all of these things with system files rather than with a 3rd party CPU app means the phone will deep sleep more, and be more responsive, because there is no app constantly running in the background trying to make changes on the fly. Also, you can find "battery saver" scripts that can be put into the above files that have their own tweaks you can make if you are determined to use that governor- but battery saver tries to constantly stay at the minimum speed possible(if you read it in some places, it simply stays at minimum speed PERIOD), and will have the most extreme lag, with a questionable amount of increased battery life compared to a tweaked on_demand governor.

And last, before undervolting, try decreasing the max speed of the core.. you can lower it by 1-2 steps and notice NO difference in speeds, yet get far better gains than undervolting, without creating instability. The volts that HTC chose are probably the very minimum that works well for all of our phones, as undervolting by 12.5 may work fine on my phone, but may introduce random reboots or worse on yours- once you undervolt you simply can't troubleshoot any issue on your phone, because the UV could be the cause instead of anything else..

There is more than that you can do also, like making sure that your screen-on and your actual usage numbers are almost EXACTLY the same- get an app like betterbatterystats(available free on XDA) to see what partial-wakelocks are keeping your phone from deep-sleep.. the higher the % of deep sleep, the less you have to worry about ANYTHING to do with the CPU, since the CPU isn't being used at all..

If you do everything I said above to maximize battery on the on_demand governor, you can use a CPU app to change to battery saver governor when you know you won't be near a charger, and you just want basic functionality(no games, browser, etc), and DONT set on boot.. that way on reboot it defaults to normal governor.

I tweaked all the things I said above and get at LEAST 16+ hours with 3+ hours of screen on, and will get over 24 hours if I underclock to around 1.2ghz.. battery saver isn't even needed if you set everything else right.

Or you can buy 2 1900mah ankers and an external charger for 29.99 and free shipping on amazon, and simply carry the spare charged battery, and never care again.. much simpler fix if you ask me.