Interesing to see what other hardware / backbone infrastructure other people are using (might be a good idea for a new topic.).
32 GB of RAM and 8 cores (what speed are they running at?) seems a bit of an overkill for a server (unless you are running it within a datacentre environment!), but seeing that you are using your server like a workstation with a desktop environment / X installed, I can understand the need for the high specifications. Does your bios / cpu support hardware virtualization (either VT-d or IOMMU support)?
Out of interest, as you are running Nethserver within a Virtualbox environment, how many processors and how much RAM have you given to the Nethserver environment?
I am not sure of the minimum hardware specification for Nethserver, but I reckon that Nethserver could be installed and run on a minimum based PC (eg. 1GB RAM, 2Ghz single core cpu, 10GB hdd)
I have installed and running Nethserver / CentOS on a Duel core (2.70Ghz), 4GB RAM, multiple HDDs (30GB root partition 5GB swap), 2 wired NICs (eth0 and eth1) and 1 wireless NIC (wlan0). The actual pc is a IBM Lenovo (modal: M75).
Obviously, as I am not using any DE / X-server and only accessing the server via ssh and the web interfaces (using both Nethserver and Webmin admin panels), the system is using only a small amount of the PC’s resources.