I got my moment about one month. I noticed the alarm clock sometime worked, sometime not. especially set up run time over 5 or 6 hours. If it passed the setup time, the alarm clock didn't run, but the setup time still showed on the locked screen(before you unlock your phone). It should show the next run time, not the last run time. I use advanced task killer to kill everything before I go to bed. Is that related? Or it has some problem with the phone? Anyone has some advices?