ABZU is a beautiful, wondrous game to play, but it can be extremely demanding on your PC, depending on your native resolution, in-game settings, and other factors.
If you are experiencing performance/framerate issues, try a lower Render Res in Settings. You may have the game set to render the game at a resolution higher than your display resolution, which provides excellent image quality without the need for filtering, but can result in a significant reduction to framerate.
Beyond Render Res, try a lower Fish, Shadows, or Reflections detail level in Settings. Fish and Shadows have been shown to be the most demanding in our play sessions and testing.
If you are running the game off of a traditional non-SSD drive, ensure that it is optimized and defragmented to help reduce hitches due to seek/read times during gameplay.
Recording, broadcasting, virtual desktop, and remote sharing applications can also have a negative impact on ABZU's performance. Please be sure to disable any apps that you aren't using before running any system-intensive game.