
You can change from the moto kernel control.... and it controls the processor(s) - dual core is not really a dual processor it is dual core with a single bus interface and a single linked cache. The OS sees it as two processors and most apps use just one unless they are specifically written to use both. Speed wise there linked to each other- Check out wikipedia or intel or amd to learn what dual/quad/etc core processors are and are not.
When you change the speed of one, it changes it for all. (anyone a pc overclocker does not speed up or slow down one core, the change interface speed, the bus speed (which is the core bus) and the voltage to make the chips behave at the new speeds.
The locked bootloader does not mean you cannot underclock. It does mean you cannot change the kernel to one with features not currently on the stock kernel. That being said yes you can underclock. Set CPU crashed and locked up ALOT and does not play well with mot_hotplug (the stock governor) The stock kernel cannot be overclocked yet since to do so would run it outside its written parameters. Underclocking is within its written parameters.. So you can underclock it. I do and have since I rooted mine day two after buying it. ( I gave stock 886 a chance, it was bad, 893 is better)
the phone stock has 4 slots for the processor included. 300 (slot1) 600 (slot2) 800 (slot 3) and 1000 (slot 4)
I played with a few apps and Jrummy's Android Overclock has worked the best for me. You might have a different experiences. Again mot_hotplug is not the governor you will want. On demand is.
Android Overclock gives you the options for using all 4 slots and all the available governors the shipped kernel supports.
If you run a th3ory rom it has the mod pack that also lets you change governor to one that is like the on demand. the overclock app has mot_hotplug hotplug ondemand, userspace and performance governors you can check.
You will want to enable and boot and add profiles.
I use in call 800-1000
battery <25% 300-600
screen off 300-600 and
charging fill 600-1000.
When my screen is off I loose about 10% in 4 hours. Which with the spotty 4g in my area is GREAT compared to without it. I set my sampling rate at 30000 up threshhold at 95 and powersave bias at 0 and check ignore nice load and apply at boot (all found in the advanced extra settings)
Hope this gets you on the path to more battery. Also if your running Th3ory rom there is a script to change from Mot_hotplug to a conservative cpu governor , read the OP on his rom it will show you how.