A-Tech 4GB Memory RAM for Dell OptiPlex 3020 - DDR3 1600MHz PC3-12800 Non ECC DIMM 1Rx8 1.5V - Single Desktop Upgrade Module (Replacement for SNP531R8C/4G) at Amazon.com
Dell Optiplex 3020 MTW,Intel Core I5-4590 3.3GHz , 16G RAM, 256G SSD + 1T WIFI , BT , DVD ,VGA/DP, Windows 10 Home 64 bits Multi Language Used Grade A - Walmart.com
4GB Memory for Dell Optiplex 3020 Micro DDR3L 1600MHz SODIMM RAM (PARTS-QUICK Brand) at Amazon.com
Dell Optiplex 3020 Adding RAM - YouTube
OFFTEK 8GB Replacement Memory RAM Upgrade for Dell OptiPlex 3020 (Small Form Factor) (DDR3-12800 - Non-ECC) Desktop Memory at Amazon.com