i have my 3G on all the time, why?

unless you have problem with weak 3G signal around your place or the Telco is doing some upgrading then you most likely have the problem.  Also try to get the latest network+ (from nokia collection) update.

BTW, if you are on 3G, try to sync your email.  Does it take a long time to sync or at times timeout?

i using 2G all the time

3G = yes (sometime) ..but didnt have any auto restart or hang

Celcom

thats weird ...did u install any WP7 apps?

If you are willing to try.  key in ##3282 in the phone dail pad and press call.  Then select the "three dots" (bottom right corner) then setting, on the network type select 3G then back out.  On the safe side shutdown and restart the phone.  See if it is stable.

this is just my opinion...it may vary with others and also your opinion...

if you could wait for the next revision, i will even advice you to wait for the next successor to 920...
as much as i like my 920 and enjoy using it, it is not without some obvious flaws...

1. mainly the heat (i'm ok with heat but not heat with the possibility of toasting the radio chip)...so far my 920 is heating up but not that hot until causes any problems yet...touchwood touchwood...

2. some windows phone 8 bugs, like random reboot, and time / date being reset after a soft reset...given this is still a new OS, this is expected...i'm ok with the bugs so far, nothing major until it breaks my usage of the phone...

3. apps are coming, but somehow i feel like developers are still skeptical about WP8 platform...

4. if you are a heavy google services user, i advice against you getting WP8 devices...

other than that, 920 is a good phone to use, and i dont regret being an early adopter of WP8...

im kindda agree with lipfung, the heating on L920 is total unacceptable. if compare with other windows phone that running 7.5 or 7.8 not even can feel the heat that rise faster than 920.

with my previous smartphone i can 24/7 on my Data connection and during day time i can even on all my data/bluetooth/wifi. now, i have to practice switching OFF my phone if the temperature rise above the abnormal level for 5min , and switch off data & goes to flight mode before i go to bed.     

look like L920 ain't smartphone , because have to be extra careful not to toast the radio like i did earlier. 

in and out my L920 have visit NC twice, only the third time when i voice out to their top level then they wiling to replacement mainboard and waited for 1month     

yeah, the heat kindda scared me away for getting the wireless charger. try to imaging after charged

CPU/Radio heat + center of the body heat up during charging... after done charging its like holding a toasted bread