How to Upgrade HP Elitebook 840 G3 Memory - YouTube
HP® EliteBook 840
16GB Memory for HP EliteBook 840 G3 DDR4 2133MHz SODIMM RAM (PARTS-QUICK Brand) at Amazon.com
HP EliteBook 840 G3 Core I5-6300U 2.4GHz SSD 180Gb RAM 8Gb with HP dock station [Y1Y02US#ABA] - $599.00 : Professional Multi Monitor Workstations, Graphics Card Experts
How to add RAM on HP EliteBook 840 G2 - YouTube
HP EliteBook 840 Upgrade RAM SSD Battery - YouTube