Well, let me just say that it's going to be very hard to pick out the differences anyway, primarily because the situations in which you can take truly identical screenshots on different machines are quite limited.
That said, here's a shot I took with the UT2K3 demo on the DM-Antalus map. This was taken at one of the spawn points, so please try to keep respawning until you end up at this exact spot, then take the shot. Also, please try to remove your weapon from view, for the best possible look at the scenery.
P.S. This will be my first test of the new setup. It should work, but please let me know if it doesn't, including any error messages.