id	summary	reporter	owner	description	type	status	component	version	resolution	keywords	cc	guest	host
10997	Upload speed problem for virtualized Windows 7 or XP and NAT	Ladislav Nesnera		"I have the same problem as described here - http://www.appleimac27.com/2012/08/25/how-to-fix-windows-8-virtualbox-upload-speed-problem-on-imac/ i.e. upload is significantly lower in the guest then in the host (0.18 versus 2.75 Mbit/s)

I can't use suggested workaround (switch to Bridge) because it is impossible for 3G modem.
Very Interesting is that virtualized Ubuntu has full upload speed with NAT

Host OS - Linux nb 3.5.4-1.fc17.x86_64 #1 SMP Mon Sep 17 15:03:59 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux (Fedora 17)"	defect	closed	network/NAT	VirtualBox 4.2.0	duplicate			Windows	Linux