 Halo 3 does not natively render at true HD resolution ( at least 720 lines of vertical resolution ) . In a Bungie Weekly Update , it was confirmed that the game renders at 1152 × 640 resolution instead of the usual 1280 × 720 ( HD ) resolution that most Xbox 360 games use . This is because Halo 3 uses two frame buffers instead of the usual one , so the lower resolution allowed Bungie to preserve as much of the dynamic range as possible for the game 's lighting without adversely affecting the frame rate . The image can be upscaled to 1080p by the Xbox 360 . 
