By my reckoning, it is gaining maybe a minute to a minute and a half per week. Doesn't sound much, but it starts to add up unless I keep it in check.
Not to mention of course, that it really shouldn't be happening at all. I have tried looking on the marketplace, but can't find a single auto time updater. My old Nokia had an option to set the time via the net and was always bang on.
No that's definitely missing. I have the 24hr clock option and then the manual settings below it. I'm in the UK so maybe that is a factor. Although my old phone (nokia 5530) was with the same carrier (T Mobile) and definitely had an automatic option.
In that case the only other thing I can think to do is contact your cell provider and make sure they have the correct IMEI registered. I know some things won't show up on my device like internet sharing for example. If I am using a device that's not registered internet sharing won't even be in the options list.
It happens (all the time) to my lumia 710 also. It's stupid that such new and smart(?) phones can't do such a simple task like keeping the time correctly And it's also strange that there isn't really anything to do about it :/ Nokia 3310 would show correct time even after 100 years while being without battery :D