parts-quick 16GB Memory for Dell Optiplex 7040 Micro DDR4 2133MHz SODIMM RAM at Amazon.com
Dell Optiplex 7040 Desktop Computer PC, 3.40 GHz Intel i5 Quad Core Gen 6, 16GB DDR3 RAM, 2TB Hard Disk Drive (HDD) SATA Hard Drive, Windows 10 Professional 64bit Refurbished - Walmart.com
Dell Optiplex 7040 SFF | i3-6100 @ 3.70GHz | 8GB RAM | 500GB HDD | 6th Gen | Team Spares
Dell Optiplex 7040 SFF Core i5 | 8GB RAM | 240GB SSD - Green IT