I would rather you get the option 3 but with the default i5. Why? because a dedicated graphic will have more significant impact. nevertheless, it is still a capable machine for fcpx.
if you are doing video often enough, 256gb is really tight and you need to make transfer to external storage frequently.
like PetPet said, if you are going to bootcamp, 256gb is super difficult to work with because you ended up with not much storage available on both macOS and Windows.
Thanks all for the suggestion.
Hi ashhong, option 3 does not have dedicated graphics.
The options given are from the brochure given in the acceptance package from poly, not sure if I can request for any other configuration.
