Comment by makeitdouble

Yes, it might the difference on the network stacks. Perhaps it was decent on GSM ?

In asia it was the same deal (from iPhone 3G, not the original one). Most of the issues seemed to be when the phone ran from too long and/or was low on battery. From my understanding memory was leaking all over the place, and as the phone app isn't isolated from the system it was affected too (even if the network chip is a separate hardware and OS)

Basically rebooting every now and then was a good idea at the time.