I have 2 go 600 and 1 via 1625. If I update the map in all my devices, the map download takes about one hour for each device. What I think is the map download is sent to your computer first and then installed on your device. Why download the same map when it is already in the computer. Why not revise the software to look first if there is already an up to date map download in your computer and if it finds it, use that to install the same map into your other registered devices. For three devices like I have, it will save me 2 hours for 2 downloads on the next 2 devices.