After some Windows 2016 server deployments on ESXi 6.5 customers started to notice slow server responses.
I came across the following VMware article.
So after checking the build numbers on the ESXi server it turned out i was on build 5146846. I suggest you upgrade to ESXi 6.5 Update 1, build number should be 5969303 or higher
If you are unable to upgrade ESXi then use the registery settings in this VMware article.
hope this helps anyone.