"I finally found the root cause of my slow WiFi and Ethernet speeds on my Xfinity service. Check your Windows applications (Windows Key plus q on Win10) and see if SmartByte has been installed. This piece of software will interfere with your connection's peak speed, drop your VPN connections and cause other issues. You can disable it or remove it completely. It is supposed to help prioritize applications and their demands for bandwidth, but instead just messes up everything.
It is installed on all Dell PCs and laptops by default for the last several years. So, if you have Dell Update turned on it will REINSTALL SmartBytes, so your problems will reappear. "
I found this solution on another posting and it works! I went from 10 Mbps to over 100 after rebooting PC. I just removed the Smartbytes program! FYI it may not show when you do "win Q" but it will in the win10 programs listing for uninstall.