Well before giving you a ton of tips do you notice any specific error messages when it shuts off? Also are you a first time user or have you been playing for a while and now this is just suddenly happening? If you're an old user it could be that there's a corrupted, missing or misplaced file after you downloaded a mod or messed around with your files a bit. Sometimes the easiest, although annoying, most basic fix in that case is to uninstall the game and delete the Feral Heart folder then reinstall. Other fixes could be to change your rendering system from OpenGL to Direct3D9 in the main menu options\video settings. You can also attempt to lower your view distance to 0 and remove water reflection also in your video settings.
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