onboard already 8gb, u add another 8gb probably the max your laptop could use. even my gaming pc with 16gb ram running vmware (4gb ram) with 3 monitors, 20+ chrome tabs could barely fill it. laptop lagi la susah mao utilize.
also, most of my office pc upgraded from 4 to 8gb (4+4) since the ram is cheap now and all running different brand but dual channel interleaved