What helped for me was going to the Advanced tab of my Ethernet Adapter and change the value of 'jumbo frames'.
It was on the lowest setting...I have changed it to 9KB MTU.
I have a 150mbps connection and after 8 hours it only did 68mbps. Without rebooting and changing this setting it went up to 98mbps.
So an increase of 30 mbps, which I could not have done before, and it was instant.
I have installed the 23.03.2017 driver of my Realtek card, which could not be installed through Windows 10 automatically. Had to go to the Realtek site for that one.
I also disabled the energy setting that could shut down the Ethernet card.
There are more Tweaks for an Ethernet card.
I only used the Jumbo Frames, but here is more:
http://techgenix.com/advanced-network-adapter-driver-settings/
I know I am replying late in this thread. Hope it can be helpful to other Windows 10 users.