How to add Ram memory Lenovo ThinkPad E540 - YouTube
CMS 16GB (2X8GB) DDR3 12800 1600MHz Non ECC SODIMM Memory Ram Upgrade Compatible with Lenovo® Thinkpad E540 Notebook - A7 at Amazon.com
LENOVO THINKPAD EDGE E540 20C6008QUS QUAD CORE 15.6 WINDOWS 7 PROFESSIONAL BUSINESS NOTEBOOK PC (INTEL CORE I7-4702MQ 2.2GHZ, 500GB PRO PERFORMANCE SSD, WINDOWS 7 PRO LAPTOP, 16GB RAM) - GTIN/EAN/UPC 712691384931 -