I'm pretty sure the adapter that comes with the X1900 XT is a video out adapter, which means you'd plug the RGB jacks into your HDTV (or other device)... sorry to say, you probably won't be able to plug your 360 into your PC that route, unless the card is specifically VIVO for HD. You may want to consider looking into the VGA cable for 360. There are 3rd party versions of the Microsoft adapter ($40) on eBay for around $15. I've got the "Dragon" adapter, and I've been using it since March on my Dell P1130. You may need a gender changer, depending on your monitor. The 3rd party cables DO NOT come with one (though the MS adapter does). Good luck! PM me if you've got any questions. Thanks!