It can be changed as it's socket g1. The issue is the cpu support list is never published for laptops. You can try to contact dell but many times they don't have it either. You can see if other 1540 have different cpus but most of the time, laptop cpu upgrades is try at your own risk. Also a better cpu will produce more heat even if the tdp is the same so check you temps and see if it even gets too hot now.