Slava Murygin has notes on licensing SQL Server 2016:
– Two Major Licensed Editions: Enterprise and Standard;
– Enterprise Edition can be licensed only “By Core”. Standard also available on “Server+CAL*” basis;
– If you have SA** you can still use your old CAL licenses with SQL Server 2016 Enterprise Edition, but will be limited by usage of only 20 Cores on your server;
– Standard Edition is limited by 4 Sockets/16 Cores and 128 Gb of Memory;
Licensing is boring, painful, and ultimately necessary to understand.