It uses the Via Nano CPU, to deliver an incredibly low-power solution of 20-29 Watts/server when fully busy, and 15 Watts/server when the OS is idle. It includes enterprise features like 64-bit operating systems, 1-to-1 virtualization, and remote management via IPMI. What this does is turn the current server paradigm on it’s head. Instead of using more and more power hungry server chips that deliver more performance than you really need, which opens the gate for someone to tell you about server virtualization and consolidation to make the most of the power per watt, or cost of the server. The Dell XS11-VX8 just gives you “enough” performance, at a good price, and an effective price per watt. For those sensative to cross-charging, billing out IT services etc. it has another side effect of simplifying software licensing and allocation.
Over on the Direct2Dell blog community, Todd has written a post with some useful additional detail.