Following reports on the internet that Halo 3 runs at a resolution lower than 720p, Bungie has come clean and confirmed that the Xbox 360's flagship title doesn't quite meet the minimum requirements for HD resolution, with the game running at the slightly lower resolution of 1152x640.
So why is Halo 3 unable to offer a true 720p resolution? Bungie's Luke Smith fills us in: "... you could argue we gave you 1280 pixels of vertical resolution, since Halo 3 uses not one, but two frame buffers - both of which render at 1152x640 pixels. The reason we chose this slightly unorthodox resolution and this very complex use of two buffers is simple enough to see - lighting. We wanted to preserve as much dynamic range as possible - so we use one for the high dynamic range and one for the low dynamic range values. Both are combined to create the finished on screen image."
Smith adds that the lower resolution was required in order to get a "steady and smooth frame rate", something Bungie felt was "far more important" than delivering the full 720p resolution.
Although a disappointment, the truth is that most gamers will be hard pushed to notice the difference between 1152x640 and the full resolution of 1280x720. Even if you are sharp-eyed enough to notice, the game was a 10/10 before the revelation and in our eyes remains the same high quality game.
It's worth pointing out that Halo 3 isn't the first and probably won't be the last game to cut corners with resolution on the Xbox 360. Project Gotham Racing 3, Perfect Dark Zero and Tomb Raider Legend also rendered at a lower resolution and then used the Xbox 360's scalar to output at 720p. The PlayStation 3 and all its 1080p claims is also an offender with The Darkness unable to render at 720p let alone 1080p.