mobile

I am using cm 12.1 and f4k' kernel 2.1.7. When i use the phone the battery drops very fast . for ex: browsing the xda theard with wifi and in 3-4 minutes it goes down from 32 to 29℅ .
On the other hand, when i use my phone only for calling and messaging everything is good(2 days battery)
Cp set to max: 1,4; min 162 mhz,
Gov : smarassh3
I/o : sioplus
Undervolt with 75 mv
So please if you know something that can be usefull tel me