Question: What is VMXNET3?
Answer: VMXNET3 builds upon VMXNET and Enhanced VMXNET as the third generation paravirtualized virtual networking NIC for guest operating systems.
The VMXNET3 network adapter is a 10Gb virtual nic, with cards bound to it, you basically give that vm access to 4Gb of through-put, and if you attach more physical nics, you just keep increasing the through-put. With todays technology, server to workstation(1Gb Nic) file transfers are up to 60MB/sec!
Check out this link, to get the full scoop.