I updated my FreeBSD 10.0-CURRENT virtual machine today. It reached r255120 and it’s running with vtnet as its virtual network interface under VirtualBox 4.2.16. I noticed the vtnet0 interface gained 10 Gbit/s virtual wire speed. Previously the interface ran with only 1 Gbit/s virtual wire speed. The actual wire speed depends largely on the physical limitations of the computer hardware and the computational speed of VirtualBox’ internals.

This is due to a range of revisions such as r255109, r255110, r255111, and more important r255112.

vtnet0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether 08:00:27:0e:4a:ba
        inet netmask 0xffffff00 broadcast 
        media: Ethernet 10Gbase-T <full-duplex>
        status: active