Asus G750JX does not come with GeForce GTX 765m, but it comes with GeForce GTX 770M. where did you buy this laptop with GeForce GTX 765m? I guess your laptop is ASUS G750JW.
however GeForce GTX 765m and GeForce GTX 770M can play World of Warcraft from medium to High or Ultra setting without problem.
try to update NVidia Graphic driver and if your laptop has 3D display, then you should check the latest Nvidia driver from Asus Support website, because many users are having trouble installing NVidia drivers on G750JX with 3D Display if downloaded from NVidia site
if your laptop has no 3D Display, then you can check the latest NVidia driver from NVidia website...