Why is RB750GL showing so low tx/rx values?

Yesterday, I got two RB750GL routers which I have initially set up as switches. The ports 2-5 are all set to master port ether1 (using all five ports)

I try to monitor the network throughput, but all I see is that tx is about 60 kbps and rx is about 10 kbps. If I stream a HD clip from internet
IPTraf (linux network monitor) shows speeds like 5000 kbps while RB750GL only shows rx 10 kbps. So what am I missing and what is RB750GL actually showing (same values here http://routerip/graphs/iface/ether1-gateway/)? How can I monitor the network speed with RB750GL/RouterOS?