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I think you're misreading it. PS4 averages less than a perfect 29.97, meaning that it spends roughly half less than 30. Maybe it's at 28 or 27, but it's still like that half the time. At the same time, XB1 averages at 32, meaning half the time it spends below 32. This can mean 31, 30, or below 30, but mathematically it's clear that PS4 spends more time below 30 than XB1. The conclusion made is that if both were capped at 29.97, like they should be, XB1 would have a near perfect 30 fps framerate, while PS4 would not, or at least XB1 would be closer to it than PS4. It's not that PS4 is doing better because it's trying to get a perfect framerate--rather, it's performing worse and as a side effect it appears to hit a lower target than what it was aiming for better than XB1.