According to fudzilla, he ran the Radeon HD2900XT stable o/c with a score of 11,258 3Dmark06. The card at its default 745 MHz and 1656 MHz memory scores 10,650.
The overclocked one will gain some 600 points and the card was stable. It didn’t want to go any higher than 840 MHz, but maybe some other cards will. Stable at 11260 points doesn't looks bad at all and we are sure that you would get some performance boost in games.
The score breakdown