Back in June comcast raised my connection speed to 150Mbps.  Two weeks 
ago it went back down to 100.  I called to complain and was told I was 
supposed to be  getting 100Mbps.  I finally got someone to admit that my 
connection speed should be 150, but I'm still getting 100.

I didn't make any changes to the network, but something could have 
gotten changed.  Is there anything i can look in network settings to 
determine if something could be tweaked for a faster connection?

I have an Arris SB6141 modem and an ASUS RT-ACRH13 gigabit router. The 
modem (SB6141) supports speeds up to 343Mbps down.  KDE's network 
manager shows the MTU setting is set to Automatic and the box is checked 
to allow auto negotiation.

I did install Kubuntu 18 after the increase to 150Mbps.  The speed did 
not drop until a month or so after Kubuntu 18 was installed.

Since the installation, the ethernet connection is no longer called 
eth0.  Now it's called enp4s1.  Is that some new way of naming network 
devices?  I don't really care what it calls the parts as long as they 
work.  I can still use netwatch, but I have to give it the enp4s1 string 
as it expects eth0 unless  told differently.