So you think you know Vmware, you have recently upgraded to vSphere 4.0 and you provision a new virtual machine, using the standard E1000 Nick (basically an Intel Pro 1000 Network Interface Card), you have bound 4 1Gb Nics to the virtual switch that the VM is on, so basically, your OS will only get 1Gb max through-put. Want more? That’s easy, bind a vmxnet3 adapter to the vm and you will now open up that pipe.
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.