Dell OptiPlex 990 Tower PC, 3.2 GHz Intel i5 Quad Core Gen 2, 16GB DDR3 RAM, 1TB SATA HD, Windows 10 Professional 64 Bit (Refurbished Grade B) | Macworld
Dell Optiplex 990 CPU and Ram Upgrade - YouTube
FAST Dell Optiplex 990 Desktop Computer I5 3.1GHz Windows 10 Professional 4GB Ram 160GB DVD-RW WiFi 17" Dell LCD