Dell EMC PowerEdge R640 Installation and Service Manual The Dell EMC PowerEdge R640 system is a 1U rack server that supports up to: Two 2 nd generation Intel Xeon Scalable Processors 24 DIMM slots 8 x 2 5-inch hard drives or 4 x 3 5-inch hard drives on the front panel, or 10 x 2 5-inch hard drives on the front panel with optional support for 2 X 2 5-inch hard drives on the back panel Two AC or DC redundant power supply units