Ever since Batman: Arkham Knight released, it has been a near complete mess on PC.Things got so bad for the game, that sales for the PC version were suspended while the console versions basked in light of critical acclaim.
In July PC players saw an "interim" patch for the game that would "address many of the issues." Following that update, we learned of an update-in-progress for the game that was set to come in the "next few weeks."
It looks like someone made a whoopsy at Warner Bros or Rocksteady and set the the currently-in-development game update live. According to players that got their hands on the beta update, things are changing for the better with it. Players are claiming that the game is running at around 60FPS with maxed graphics settings, all while NVIDIA Gameworks was running (it was killing games in the past). Some mixed reviews claim the game is still "laggy and crappy" with the beta update, but I assume they do not know that a beta means it is still in testing.
The update has been removed from Steam, but some users have made it available to those that wish to try it out.
