CMS 8GB (2X4GB) DDR3 10600 1333MHZ Non ECC DIMM Memory Ram Upgrade Compatible with Dell® Optiplex 990 Dt/Mt/Sff, Ultra - A69 at Amazon.com
Restored Dell Optiplex 990-D WA1-0376 Desktop PC with Intel Core i7-2600 Processor, 8GB Memory, 2TB Hard Drive and Windows 10 Pro (Monitor Not Included) (Refurbished) - Walmart.com
Optiplex 990 Ram Flash Sales, 60% OFF | ilikepinga.com
Dell OptiPlex 990 – Refurbished – We Got Tech
OptiPlex 990 Desktop (DT) Removal Guide for the Memory, Intrusion Switch, Internal Speaker, Heat Sink and Coin Cell Battery | Dell US