The actual speed of the link will be 80% of the setting in QoS. For example, if you setup 4000/4000 in QoS and the ISP provides you with a 4000/4000 connection, your actual speed will be about 3.2M. This is by design for best quality and throughput. However, if you want to use 100% actual speed and you’re sure your link is stable, you can setup QoS higher than the ISP’s specified connection rate. For example, for a 4000/4000 connection, you could setup QoS as 5000/5000.
This is with bandwidth set to the default 10000/10000
This is with bandwidth set to 4000/4000
This is with bandwidth set to 3200/3200
This is with bandwidth set to 2000/2000
Note: The 80% default QoS for WAN1 on a Vigor2820 can’t be changed via the GUI. The displayed connection will show the ISP speed, but the actual speed of the link will be the default 80%. This can be changed using telnet command adsl txpct/rxpct for WAN1. So if you want to setup 100% actual speed, you can telnet the command ‘adsl txpct 100%’ or ‘adsl rxpct 100%’.