rMBP 15" might have something like the 765M which is found in the new Razer Blades. The 14" version of that has a similar overall size to a 15" rMBP so might be.
The rMBP does have the retina screen though, so depending how much power that draws (vs the 1600x900 Razer (I think)) it may have one of the lower cards.