I have a model of the Dell Latitude E5540 with a 4GB ddr3l 1600MHz CAS11 stick in it (I believe). I would like to upgrade the RAM in this laptop and am wondering if I can upgrade to 12gb. If I purchase an 8gb stick with the same CAS and clock speed as the 4gb stick already in the laptop could I populate the empty second slot with the new 8gb stick and make the system run on 12gb total?

Thank you