I tried to find the same problem in the forum but got no results.
So here it is :
Since the 2.1 official update my alarmclock has a pretty anoying bug. For example when I set it to ring 7:10 AM, it really rings at 7:17 AM. I tried other time and day of settings but it is the same result. Always 7 to 10 minutes off.
I tried installing desktopclock.apk yesterday and today and once again it was off 6 minutes.
Please tell me that someone as a solution .