I've recently wired my pc for ethernet (was using powerline networking) and I've discovered that my ethernet speeds seemed to be doing some weird things

I have a home server with a samba share set up, and I get 75MB/s at best which I was OK with, however transfers will often appear to be capped at 50MB/s and sometimes as low as 30MB/s

If I ipconfig /release and then ipconfig /renew (I have the MAC bound to 192.168.1.2) it usually restores the transfer speeds to 75MB/s even though it's getting the same IP address.

A reboot sometimes fixes it. It's a realtek gbe, latest drivers, Windows drivers too, have disabled any sort of power saving, manually set the transmission speed to 1gbps etc

I also have 500mbps Internet, and when its capping the lan transfer speeds I only get a maxyof 350mbps Internet speed until I do the release/renew

I've done iperf tests when it's doing it and it matches the capped transfer speeds

I've made sure QoS is off on my router too

After some investigation I noticed the "traffic monitor" option was running. 

I disabled this and I now have rock solid LAN and WAN speeds, and my SMB transfer speeds are consistently at 115MB/s. 

TLDR - turn off the Traffic Monitor