Used - Dell OptiPlex 990, DT, Intel Core i7-2600 @ 3.40 GHz, 16GB DDR3, 500GB HDD, DVD-RW, Wi-Fi, VGA to HDMI Adapter, NEW Keyboard + Mouse, Win10 Pro 64 - Walmart.com
Dell OptiPlex 990 SFF Desktop Intel Quad Core i7-2600 3.4GHz 8GB DDR3 RAM 500GB HD DVD-RW WiFi Windows 7 Professional 64-Bit USED with FREE 3 Year Warranty provided by CPS. - Walmart.com
ddr3 ram 2600 - Newegg.com
4GB SNPP4T2FC/4G A8733211 240-Pin DDR3L UDIMM RAM| Memory for Dell
ADATA Introduces XPG Gaming v2.0 Series DDR3-2600 Modules | TechPowerUp
CMS 32GB (2X16GB) DDR3 12800 1600MHz ECC Registered DIMM Memory Ram Upgrade Compatible with IBM® System X3500 M4 (E5-2600 V2) 7383-Xxx for Server Only - B17 at Amazon.com
A-Tech 32GB Module for IBM System X x3650 M4 (E5-2600) DDR3 ECC Load Reduced LR DIMM PC3-12800 1600Mhz 4rx4 1.35v Server Memory Ram (Equivalent to OEM 46W0678 47J0227 46W0676) at Amazon.com