Internet speed is not stable, from 2-80 mbps (pay for 200mbps)

We are paying for 200 mbps internet plan, but got 2-80 mpbs donwload speed. 

It varies a lot. Usually after restarting the modem will increase the speed.

Here's the log from our modem. There are  a lot of uncorrectables in the log, is it normal?

https://imgur.com/5jzQfQh