4GB RAM Memory for HP ProBook 4510s DDR3 Black Diamond Memory Module DDR3 SO-DIMM 204pin PC3-10600 1333MHz Upgrade System Specific Memory - Newegg.com
How To Tutorial - HP Probook 6540b memory replacement - YouTube
4GB Team High Performance Memory RAM Upgrade Single Stick For HP - Compaq ProBook 6455b 6540b Laptop. The Memory Kit comes with Life Time Warranty. at Amazon.com
HP ProBook 6540b RAM UpGrade - YouTube
MEMORIA RAM SODIMM 8GB 2x4GB PC3L-12800S DDR3L per HP PROBOOK 6560B - 1.35V EUR 49,90 - PicClick IT
Solved: ProBook 6450b RAM update wthat is about F1 & F2 - HP Support Community - 8164172