Just completed the update, using the VW Discover Care software, on my laptop.
My broadband speed is 150 Mbps, but the laptop Wi-Fi connection is around 40 Mbps. The update took about 1 1/2 hours.
The last time I tried this was on my desktop using an external card reader. Discover Care did not work and I had to download and install the maps manually. So the VW update software may not work with certain hardware.