Benchmark Results: Borderlands 2
The opposite is true in Borderlands 2, as both the AMD and Nvidia boards run a bit slower under Windows 8. The loss is more severe on the GeForce GTX 660, though. We ran this benchmark several times in order to confirm its outcome.
If you look at the GeForce's frame rate over time, it's clear where the differences between Windows 7 and 8 occur, though they're not particularly significant.