If you're unlocked and rooted, will SetCPU work to overclock/under volt? If so, what settings seem to be working for you?
Apex kernal has been released, in 3 varieties: "stock" 1.2 ghz, oc'd 1.35 and oc'd 1.4
I'm on 1.35 right now, very stable so far I have had no problems whatsoever .And yes you use SetCPU to tweak it. Also has slight undervolting built in, and the ability to tweak that in SetCPU as well, to help save on battery life. Read this whole thread, a lot of questions will be answered already: [KERNEL][GSM/LTE][IML74K] "Apex" Kernel (UV/OC/GPU) (12/19/11) - RootzWiki
Enjoy!
EDIT: Should have mentioned that.. sorry.. yes that kernel needs you to be on 4.0.3. DO NOT try to flash it if your on 4.0.2.
Where did you get the 4.0.3?