[VirtualBox] FreeBSD guest freezes under consistent network load

[Yuri]

Both host and guest are 10.1 amd64
Guest by itself works fine, until I try to rsync the large file out over 
ssh. When such rsync is few minutes in, random commands (mkdir/w/xterm) 
begin to freeze in guest. It looks like it loses the ability to launch 
new processes. Condition persists even when the large rsync finishes. VM 
needs to be powered down. Condition is repeatable.

virtualbox-ose-4.3.26

Yuri