Memory RAM Upgrade for Dell Latitude E5540 8GB DDR3 SODIMM | eBay
16GB 2 x 8GB DDR3 1600 Notebook Memory RAM Dell® Latitude E5540 Notebook - A7 - Newegg.com
Refurbished: Dell Latitude E5540 15.6" LED Laptop 4th Gen Intel Core i5 Mobile CPU 16 GB DDR3 RAM 500 HD DVD-RW WiFi Bluetooth Microsoft Windows 10 Professional 64-Bit - Newegg.com