Some users may experience issues with slow upload (usually 1.0 Mbps, or near there) with Ethernet connections, especially after updating to Windows 10 1803 (April 2018 Update). This can typically be resolved by uninstalling and reinstalling the Killer Control Center after the Windows 10 1803 update. Here is the step by step:
Please note that the Killer Software Uninstaller removes files and folders from previous installations that will not be removed simply by uninstalling old versions.
If you wish to know more about the differences between the two versions of the Killer Control Center, please see this article - https://www.killernetworking.com/driver-downloads/kb/faq/100-which-killer-control-center-should-i-install