CMS 8GB (1X8GB) DDR3 12800 1600MHz Non ECC SODIMM Memory Ram Upgrade Compatible with Asus/Asmobile® X Series Notebook X540LA, X554LJ-XX1153D - A8 at Amazon.com
ASUS X540 Disassembly of base upgrade ram install hdd caddy dvdwriter replace battery motherboard - YouTube
Can I upgrade my laptop RAM (ASUS X540L) from 8GB to a 12 or even 16GB? - Quora