Somewhere in the xbox vs ps3 religious wars it was discovered that you can deduce the internal rendering resolution via a technique called "pixel-counting". This involves very bored people looking at the individual pixels with a magnifying glass & counting jagged edges.
The info is solid, but its of no real use beyond the ps3-xbox wars.
I have a considerably larger monitor and have been going past that, but would love to know more about detailed specs like this to better tune the game