These specific units are so cheap because of the 'low-end' motherboards of the nodes which allow low-end Bronze/Silver/Gold CPU's only. Take little bit more money in your hands and get nice Nutanix nodes for better high-end CPU support > 205W/255A which are also thrown out the last 2-3 months.
EDIT: The Bargainhardware units are similar to the Nutanix nodes
EDIT: The Bargainhardware units are similar to the Nutanix nodes