It was long suspected.

The detailed environments in Halo push the Xbox's graphics hardware to the limit, as evidenced by the slight framerate problems right up until release. The VGA adapter for the Xbox went AWOL, and Microsoft updated the Xbox FAQ to indicate that connecting the Xbox to a monitor wasn't possible.

Put together, it suggested that perhaps Halo would be producing output at a resolution appropriate for a standard TV-- 640x480-- even if connected to another device.

And now we know it's true. Matt Soell has responded to a thread in the HBO forum about some display problems experienced by someone using a Sony Wega KV36-XBR400 with the Xbox HD AV Pack.

Matt had this to say:

Both Jason and Joseph are out recuperating from illness and/or surgery, but I asked Marty and Jay about this. Neither one had a definite answer, but we're all 99% sure that Halo outputs the same resolution (640x480) all the time. Not sure why the picture would seem more or less aliased at any given time, because I don't think we change resolutions or anything else during gameplay that would cause that.

I'm sure the picture still looks better on an HDTV than a standard one, but it looks like even if you have one, or the mysterious VGA adapter reappeared, you'd still be using the 640x480 resolution. Question is, what does that mean for Halo on the Macintosh and the PC? And what illness and/or surgery has befallen Jason and/or Joseph?