You're computer is not top of the line (because top of the line means best ). Judging from your specs, medium detail should work fine for you. You can try high setting to see how it runs. The game looks fantastic even on Low settings so don't sweat it. Whatever you do, don't turn off the advanced settings like lighting and bump-mapping because it really ruins the experience. Go to http://www.hardocp.com and check out the Official Doom III Hardware Guide.