Haven't changed a thing ... everything's running totally standard.
XT came from Microdirect - check out my review of them on the users bit for more info.
Realistically I can't imagine a slightly higher 3D Mark having much effect in gaming, but it is a little galling to be so far off the mark. I did briefly attempt to use the Overdrive feature in the ATi control panel and the 5% auto-overclock on the mobo but I saw very little difference at all.