Display
Resolution: Resolution has a significant impact on FEAR's performance. FEAR is limited to 4:3 aspect ratio resolutions such as 1600x1200, 1280x960, 1024x768, 800x600 or 640x480 if selected here. Note that the actual resolutions available to you depend on your video card and monitor capabilities. The lack of popular resolutions like 1280x1024 is because the developers only officially support proper 4:3 aspect ratio resolutions and further they have also stated that users should avoid any resolution above 1024x768 as it is too strenuous for most current systems. This is not true - I can confirm that the latest 7800GTX and X1800XT cards can indeed perform extremely well at resolutions above 1024x768. Fortunately you can set a custom resolution like 1280x1024 by editing the .cfg files - see Settings.cfg under the Advanced Tweaking section of this guide.
Update: Note that as of the 1.08 Patch, widescreen support has been added to the game (See page 4 for details).