@Duitser 

Hi,

When you use the other to test the speed of the SIM card, please test at the same place, and use another 4G router or enable a hotspot on your phone and check how much speed you can get from the WIFI/hotspot.

If the speed is still slow, please try the following troubleshooting steps:

1) Go to Advanced -> Network -> Internet page and change Network Mode to "4G Only" especially when the router is working on 3G.

2) Try another available APN profile or create a new APN profile manually.

3) Change Wi-Fi channel and channel width on Advanced -> Wireless -> Wireless Settings page.

If all the advise above cannot help, please contact the local support team with the results with the troubleshooting steps.