The Mafia II engine passes physics handling over to the NVIDIA PhysX libraries and takes advantage to offer high physics settings which can be partially accellerated by the GeForces.
To measure performances we used the built-in benchmarks and all graphics options were pushed to a maximum, except for PhysX effects accelerated by the GPU:
The GeForces have a big advantage here, benefitting from what appears to be a more significant CPU limitation on the Radeon side as well as the fact that the quad CrossFire X systems are inefficient.
Mafia II can detect that a large display area is made up of three monitors and therefore recognises the resolution as 3x 1920x1080 and not 5760x1080, which means it can automatically adapt the interface. For reasons unknown however, this detection system fails with a Radeon HD 6990 + Radeon HD 6970 pairing (triple CrossFire X) as well as with the GeForce GTX 590 pairing. The interface is then unusable and the rendering of the benchmark mode is only displayed on one screen.
On the GeForce side, activating antialiasing has no effect. We imagine that NVIDIA must have blocked the activation of antialiasing in its drivers to prevent the impact of lack of memory.