I've got a dedicated webserver (debian 6) running with plenty of unused capacity. While the remaining capacity isn't used i thought it'd be nice to create a virtual machine to work on using RDP.
What i tried
I've started trying VirtualBox (no specific reason), created a VM and installed Windows 7 on it. I have only 1 IP address so had to use NAT for the networking. Using the VirtualBox settings i set up some port forwarding to get RDP working.
While that worked i thought it was quite slow (screem slowly got built and only few changes where executed at once). The server has Gigabit connection (tested and works fine), i have a download speed of 120 Megabit (10 up).
I did a speedtest on the VM and the speed was awful. 2 Mbit down, 3 Mbit up. After some googling i found that it had to do with the VirtualBox network buffer sizes (http://techblog.geeksbrain.net/2012/11/how-i-solved-slow-windows-upload-speed-when-using-virtualbox-nat-or-bridged/) And also how to fix it. Increasing their size DID increase my speedtest results to 70Mbit down and 60 Mbit up but RDP barely worked at all. It got very very slow and would often lose connection.
What I want
And so I have yet to get my virtual workstation usable. Basically what I want is to get a windows VM running which is capable of using about all my unused resources (probably a little less). It cannot have a online IP address of it's own since I have only 1. It has to be accessable via RDP.
The actual question
What should i do to get the above ('What I want') running? (Doesn't have to be VirtualBox, anything that works is fine)