Benchmarks: Just Cause 2, Mass Effect 2
Just Cause 2 allowed the GeForce GTX 580 to beat the Radeon HD 5970 by 3%, while it was 14% faster than the GeForce GTX 480 and the Radeon HD 5870 was separated by an enormous 43% gap. It is interesting to note that these are the exact same performance margins seen in Far Cry 2.
Mass Effect 2 seems to favor AMD cards slightly, so the GeForce GTX 580 was 19% slower than the Radeon HD 5970. However, it still beat the Radeon HD 5870 by a comfortable 22% lead. That lead was even cozier when looking at the GTX 480, which performed 40% worse.