A-Tech 4GB Module for Lenovo G550 Laptop & Notebook Compatible DDR3/DDR3L PC3-12800 1600Mhz Memory Ram (ATMS278419B12034X1) at Amazon.com
4GB DDR3L-1600 (PC3-12800) SODIMM Memory RAM for Lenovo G550
NeweggBusiness - Lenovo Laptop Intel Core 2 Duo T6600 (2.20GHz) 3GB Memory 320GB HDD Intel GMA 4500MHD 15.6" Windows XP Professional preinstalled with Windows 7 Professional Upgrade Option G550(2958-A4U)
Lenovo G550 Disassembly video, upgrade RAM & SSD, take a part, how to open - YouTube