My HDTV is only 720p, not a full 1080p and I am using a HDMI cable. You can also you the component cables for your 360 and flip the switch to HD. One you have them plugged up you can go to Display Settings and pick the settings that best match your TV. Also, a word of advice for the future.
Change your title. Titles like that get on the Mods (and users) nerves, and usually a Mod will lock the thread. If you were to change the title to something like, "Using HD setting without full res" it would be a more appropriate title and probably get hit faster.
Not try to be a wanna-be mod here, just trying to give some advice.
