Just some weekend testing with two Windows 2012 R2 VM’s on the same Hypervisor and tests to see what throughput can be generated using the Microsoft NTttcp utility…
These are truly science experiments given there is no application that runs with a single IP stream between internal VM’s (such as App to DB) or to external users… By definition, every user connection would be a unique IP stream.
Overall, pretty straight forward to achieve multi gigabit performance out of the box and with more simultaneous streams, the aggregate bandwidth could easily exceed physical wire speed of the server.
The 64KB window is also a worst case scenario and certainly bigger window sizes can assist in improve throughput…