8GB KIT (2 x 4GB) for HP-Compaq 600 Notebook Series HP 620 HP 625 HP 635. SO-DIMM DDR3 Non-ECC PC3-8500 1066MHz RAM Memory. Genuine A-Tech Brand. at Amazon.com
A-Tech 4GB RAM for HP 635 635 | DDR3 1333MHz SODIMM PC3-10600 204-Pin Non-ECC Memory Upgrade Module at Amazon.com
16GB Memory HP ProBook 635 Aero G7 Notebook PC DDR4 3200MHz RAM Upgrade
HP 635 15.6" AMD Laptop Boots to Locked BIOS NO HDD/RAM/Charger JR | eBay