8GB [2x4GB] DDR3-1333 RAM Memory Upgrade Kit for The Compaq HP Probook 6550b (WZ241UT#ABA) (Genuine A-Tech Brand) at Amazon.com
HP ProBook 6550b 15.6" Widescreen Laptop - with Intel i5-520M 2.4GHz, 4GB RAM, 128GB SSD Hard Drive - Windows 7 Professional 64 - Used with FREE 3 Year Warranty provided by CPS. - Walmart.com
Hp probook 6550B Intel core i5 @2.57ghz – HDD 320GB _ 4GB RAM Notebook PC – Wene Computers
HP ProBook 6550b / 4GB RAM, 500GB HDD IntelCore i5, 2.5GHz, 15.5" / windows 10 / GRADE: A | Baudspace Warehouse
HP ProBook 6550b servicing open changing the thermal paste and changes the processor - YouTube