Hi,
Those 2 laptop looks absolutely identical with their specification and the only difference is the screen size and battery. The 14" laptop does have 4 cell and the 15" has 6 cell which is I guess is still the same it's just to compensate the screen size. So, if I were to choose between those 2 I would go for the laptop that has a bigger screen specially if you'll use it for gaming.
Here are the specification of both laptops for your reference:
GS40 6QE PHANTOM:
https/www.msi.com/Notebook/GS40-6QE-Phantom.html#hero-specification
GE62 6QF APACHE PRO: https
/www.msi.com/Notebook/GE62-6QF-Apache-Pro.html#hero-specification