Unhappy [Q] Xperia neo v battery drain

Hello everyone i have a serious problem i`ve fully unlocked my phone - bootloader etc. and i`ve installed Xperia ultra kat 2.1.1 rom with provided kernel and battery life its about 6h today i`ve charged phone up to 100% and after 2h standby no phonecalls etc. i got 80% battery, while playing songs 1-2% per song, while playing max payne for 15min i got from 72% to 32% xperia is raising temperature to 45*C only while playing games and 42*C on net. same with standard clock and oc to 1305Mhz with Smartass V2 i have task killer and i`m using it always when i stop doing anything on phone i have original sony ericsson battery BA700 and its status is good in service menu. can someone help me with it? sorry for my language still learning english