Amazon.com: Dell Optiplex 9020 Small Form Desktop, Quad Core i7 4770 3.4Ghz, 32GB DDR3 RAM, 4TB Hard Drive, DVD-RW, Windows 10 Pro (Renewed) : Electronics
CMS 16GB (2X8GB) DDR3 12800 1600MHz Non ECC DIMM Memory Ram Upgrade Compatible with Dell® Optiplex 9020 Mt, 9020 Sff, 9020 Usff Desktop - A63 at Amazon.com
How to Add RAM on DELL OptiPlex 9020 SFF - YouTube