Techincally the larger rotor due to the larger diameter is capable of producing more stress/torque on the wheel. In practical use it usually is the same due to the limits of tire traction. The deal is with a larger rotor it requires less lever pressure to apply the same amount of force to the wheel due to the rotors larger lever moment. So within the limits of the master cylinder you are able to apply more force to the wheel for the same pull at the lever. The big limiting factor is braking traction afforded by the tires. So with all other things being equal, you end up applying less lever pull to get the same braking force at the tire/trail interface as you would with a smaller rotor. The bottom line is it will require the same amount of torque or force applied to the wheel to get the tire to break loose with a larger rotor as it will with a smaller rotor, it'll simply require less effort on your part to get it to happen. The larger rotor will be capable of applying more force, but it likely won't be usable as the tire will break traction at the same point with either rotor. And as long as you are comparing the same tire and wheel combination with the smaller and larger rotor the results would be the same.