Reviews for the console version of Rocksteady's Batman: Arkham Knight have been overwhelmingly positive, but PC players aren't so happy. Users on reddit and Steam are reporting all manner of problems with the game, including stuttering, wildly variable frame rates, and crashes, to name but a few. There are also reports of memory leaks causing the game to spike to over 12GB of memory usage before crashing entirely. In response, Steam users have bombed the game's profile page with negative reviews.

While the performance issues affect both Nvidia and AMD users, including those with high-end cards like the GTX 980 running the latest "Game Ready" drivers, it appears that once again AMD users are suffering the most. Hours before the release of Arkham Knight, Rocksteady updated the game's minimum system requirements, noting that "there are some known issues with the performance of Batman: Arkham Knight for PC owners using AMD graphics cards," and that it is "working closely with AMD to rectify these issues as quickly as possible." Multiple users have reported the game dropping to below five frames per second with AMD cards.

Unfortunately, this isn't the first time that AMD users have suffered from subpar performance compared to Nvidia users, with recent releases like the The Witcher 3 and Project Cars both evincing similar issues. Like The Witcher 3, Batman: Arkham Knight incorporates several Nvidia GameWorks technologies, including Enhanced Rain, Interactive Fog and Smoke, and Interactive Paper Debris. However, unlike with The Witcher 3, those effects appear to be running poorly across both Nvidia and AMD cards. Users are also reporting that disabling GameWorks features does little to help with frame rates.

While it's highly unlikely that Nvidia's involvement with the game has had any detrimental effect on AMD's performance—despite what AMD will probably say—the fact that it runs so poorly on its own hardware is disappointing to say the least. In a recent interview with Ars, Rocksteady's Lead Engine Programmer Dustin Holm explained that a "whole team at Nvidia" was working alongside the company to develop the game.

[Nvidia has] a team of people in their GameWorks division that develops this whole new set of technologies that do some really amazing stuff that's optimized to run on their cards. They then come to us with these proposals of some ideas of things that they can integrate in. A lot of the content is developed by them—we do collaborate on some things—but a lot of it is super technical. Like, they do a brilliant fluid simulation. Up until now, that kind of simulation has been way beyond the reach of what we can do in real time, but they've got some super big video cards that can run everything we've built, but they can run a little bit extra so they can run their own stuff on top as well. It's been the same process for all the games.

When questioned on the subject of GameWorks performance and AMD cards, Holm said, "We work with Nvidia and we trust their abilities to get it running well on their hardware, which they do, and no, those [GameWorks] features don't run on AMD, but we also work with the AMD driver team to work with them on performance issues so they can develop drivers. My job is to make sure that you get a good experience, so we try our best to make sure everything is running well on all platforms."

Other issues for Arkham Knight include corrupted game files for those that pre-loaded the game on Steam, causing crashes and freezes as well as significant frame drops when gliding or calling and driving the Batmobile. The game itself is also limited to 30fps out of the box and requires editing the game's files to disable it. To do so, users have to navigate to "STEAM_INSTALL_FOLDERBatman Arkham KnightBmGameConfigBmSystemSettings.ini" and search for the line item "Max_FPS=30" and change it to "Max_FPS=9999".

Despite all the reported problems with Arkham Knight, not everyone is suffering, with some users claiming the game runs perfectly fine on their hardware. Indeed, one resident of the Ars Orbiting HQ (Britannia Module) who played the game briefly last night didn't encounter any issues at all. What makes this whole thing even more odd is that the game is running on a modified version of Unreal Engine 3, an engine that has been doing the rounds for a very long time and scales well across a variety of hardware.

Still, there are most definitely performance issues in Arkham Knight. Whether they stem from drivers, poorly optimised code, or from a shoddy PC port remains to be seen. The latter may be likely, though, particularly given Warner's track record: the PC ports of Mortal Kombat X and Injustice suffered from all manner of issues. For now, let's just hope that Warner and/or the GPU companies are working hard to get this fixed as soon as they can.