I thought that changing the adapter order in Windows Network Connections made Windows use the one that is listed first. Not sure why, but this seemed to work for me previously just fine. Today I was a client site and after installing and rebooting the PC, but 4G card still wasn’t being priorities.
Turns out, you need to change the metric of the adapters in their properties for this to work as expected. Note that using 1 and 2 didn’t work for me, I ended up using 1 and 5.
As taken from http://www.speedguide.net/faq/how-to-tell-windows-7-to-use-a-different-default-350
1. Open the Network Adapter Properties (Control Panel > Network and Internet > Network Connections > right-click on adapter and choose Properties)
2. Open the properties of Internet Protocol Version 4 (TCP/IPv4).
3. Click on Advanced and untick “Automatic Metric” and set the interface metric to a number (I used 1 and then 5 where 5 was the LAN connection I wanted to use, but not prioritise and 1 was the 4G card)
4. Hit OK until you close the Network Adapter properties.
5. Repeat steps 2-6 for your other network adapter(s) choosing different metrics.
I then closed and reopened the browser to test. I used ip4.me to check my IP and speedtest.net to check the speed. Sad that the ADSL2+ down there was getting 4.5Mbps whereas the 4G was getting 24Mbps, pity it costs so much.