How big of a difference do you guys think I would notice in running games going from 350M to 850M? My current card fails to run high-demanding/new games respectably (such as Bioshock Infinite or The Witcher 2). I would love to run The Witcher 3, and would consider medium settings at 900p/30FPS acceptable when it releases. Seem doable?
Rather huge. The 750M is *just about* on par with Playstation 3 graphics. Bioshock Inifinte looks and plays great--albeit not no par with what you'd get from a gaming pc, obviously. Oh, and Trine 2 at full retina resolution is definitely a sight to behold.
The OSX version of Witcher 2 is an extreme resource pig. Definitely playable, but not a great performer by a long shot. (And sadly, no PS3 controller support, which is really unfortunate.)
The 850M compares favourably to the 750M in every category, obviously. See here: http://gpuboss.com/gpus/GeForce-GTX-850M-vs-GeForce-GT-750M
From your 3350M? Huge jump.