Clearly, something is not quite right with Assassin’s Creed Unity — but rather than talk about Ubisoft’s disgusting 12-hour delay on reviews, or what appears to be a shoddy PC port, we’re going to focus on something rather interesting: The Xbox One version of Unity runs at a higher frame rate, and feels more responsive, than on the PS4. Given that the PS4 has a considerably beefier GPU, and should generally be capable of higher resolutions and frame rates than the Xbox One, this is a puzzling finding to say the least. What’s going on?

This early analysis comes from Digital Foundry, which is as nonplussed by the Xbox One’s superior performance as we are. Digital Foundry double-checked that the day-one patch was installed, and even ran the benchmarks on a second PS4 — but sure enough, the Xbox One has a ~5 fps advantage over the PS4, both in busy crowd scenes while barging past dozens of NPCs, and while free-running across the rooftops. Digital Foundry says that performance is still “a major issue” on the Xbox One, but it impacts gameplay less on the Xbox One than the PS4. Reading between the lines, it actually sounds like the guys at Digital Foundry found Ubisoft’s latest game to be a pretty jarring and unpleasant experience.

The big question is, why does Assassin’s Creed Unity run better on the Xbox One? We know that the Xbox One has slightly more CPU power available — and that Ubisoft has previously said that Unity is CPU-bound, due to the general complexity of the game and the number of NPCs requiring AI. This doesn’t fully explain why the Xbox One beats out the PS4 in rooftop sequences, though.

Another possibility is that the Xbox One version of Unity is more optimized — either due to Ubisoft spending less time on the PS4 version, or simply because Microsoft’s developer tools and compiler create better code than Sony’s. Given how the game was clearly rushed out in time for the holiday season, I wouldn’t be surprised if Ubisoft just didn’t get around to optimizing the PS4 version.

It’s also worth pointing out that the PS4 has a consistent lead over the Xbox One of a few fps during cutscenes — which would definitely seem to indicate the CPU is involved in the Xbox One’s advantage during gameplay (cutscenes are almost purely GPU-bound), but it doesn’t tally well with the PS4’s frame rate drops during sparse rooftop sections. It’s actually also possible that the consoles’ differing DRAM/ESRAM setup could be a factor, too — new engines can definitely stress memory bandwidth.

Read: Assassin’s Creed Unity is beautiful on the PC – and tuned exclusively for Nvidia GPUs

Ultimately, it mostly sounds like Assassin’s Creed Unity is just a bit of a mess. The game — which is powered by a new version of Ubisoft’s AnvilNext engine — certainly looks good, but perhaps Ubisoft didn’t leave itself an adequate amount of time to tune the game/engine so that it runs well across the consoles and PC. It goes without saying, but it’s just downright sad that the next-gen consoles can’t stick to 30 fps, even when running at the low resolution of 1600×900.

The good news is, most of Unity’s issues can probably be fixed with some patches, and on the PC side of things new graphics drivers from AMD and Nvidia might help things along as well. Something tells me this won’t be the last time that we talk about Assassin’s Creed Unity.

Now read: Xbox One readies shift to 20nm – but can a smaller node help it match the PS4’s performance?