Hi I have UPDATE: It seems that tests from level505 were just confirmed link: http://www.ddworld.cz/graficke-karty/atir600-alias-ati-radeon-x2800xtx-testy-potvrzeny.html
Its in czech. BTW I know this guy and his info is most of the time very reliable - according to this info tests were done by someone from Microsoft with WEAKER version of X2800XTX on very early drivers which were modified by tester.
http://www.ddworld.cz/images/stories/grafiky/R600 2/fake.jpg