According to a post on Bethesda’s official blog, The Evil Within will be running at 30 fps upon its release on Xbox One, Xbox 360, PS4, PS3, and PC.
Although there are ways of altering the framerate for PC players, the blog post specifically mentions that such alterations are neither supported nor are they recommended. According to the post: “The team has worked the last four years perfecting the game experience with these settings in mind. For PC players, we’ll provide debug commands on how you can alter the framerate and aspect ratio, but these commands and changes are not recommended or supported and we suggest everyone play the game as it was designed and intended for the best experience.” There was also plenty of information about minimum specifications and other such technical questions within the post that you can check out.
Bethesda apparently intended for the game to run at 30 frames during the design process: “Shinji Mikami and the team at Tango designed The Evil Within to be played at 30fps and to utilize an aspect ratio of 2.35:1 for all platforms.”
The Evil Within will be available for pre-load on October 10 on Steam and October 12 on PS3 and PS4. The game itself will be available on October 14th in the US and Europe.