Clock on A855 gaining time

[A1 Handy]

I have to the best of my ability set the clock on my Droid A855. It seems to gain about 5 minutes for every 2 minutes actual time. I can set it for 12:00 and go back ten minutes later and the display will say 12:20. This is the clock that comes preinstalled on the phone. Whats happening and how can I correct t his.