Update: Well, we've got an official answer about this! Pentiment Director Josh Sawyer has confirmed the omission of 120FPS on Xbox is "just a bug", and the feature will added to the Xbox version in the next patch.
Original story: Obsidian Entertainment's Pentiment is the first of Xbox's four in-house titles to move over to other platforms, and its recent release has brought about a baffling discrepancy between the Xbox Series X and PS5 releases.
As you can see in the video up above (and via other sources) Pentiment appears to be running at a muchhigher frame rate on PS5 than it does on Xbox Series X. The PS5 version seemingly pushes 120Hz playback when used with a compatible display - the Xbox version only runs at 60Hz in this same case.
We're not sure what's causing it as there doesn't seem to be a manual 120FPS toggle anywhere, and we'd imagine Obsidian will spot and fix this. We must admit though, we'd like the fix to include a 120Hz option on both systems rather than just limiting the PS5 version to 60FPS!
We haven't had access to the game on PlayStation 5 here at PX so we can't confirm the difference ourselves, but this certainly seems to be happening - it's a curious one! We'll keep our eye on things in the coming days and hope for some sort of explanation from Obsidian.