I find that the N900 is very reluctant to switch from 2G to 3G while it is connected to a VPN session (OpenVPN). If I connect to the VPN in a 2G area and drive to a 3G area it takes a very long time for the N900 to switch to 3G if the VPN link is under load (such as if the N900 is constantly pinging the internal VPN gateway).

The same applies if I start off on 3G, connect to the VPN and move to a 2G area... the N900 stays on 2G for a very long time even if I move to a 3G area again.

Does anything have any idea about this?