Upgradeable Memory Options for 4400 Series Routers (4451 and 4431) | MEM-4400-2G= 2G DRAM (1 DIMM) for Cisco ISR 4400, Control Plane or Data Plane, Spare * MEM-4400-4G= 4G DRAM (1 DIMM) for Cisco ISR 4400, Spare * MEM-4400-8G= 8G DRAM (1 DIMM) for Cisco ISR 4400, Spare |