OFFTEK 1GB Replacement Memory RAM Upgrade for Dell OptiPlex 390 (Desktop) (DDR3-10600 - Non-ECC) Desktop Memory at Amazon.com
Amazon.com: Dell Optiplex 390 Business High Performance SFF Desktop Computer PC (Intel Quad-Core i5-2400 up to 3.4GHz, 8GB DDR3, 1TB HDD, HDMI, DVD, Windows 10 Pro 64-bit) (Renewed) : Electronics