Can you run Vantage on the extreme preset perhaps? If there is no noticeable gain from stock and that overclock on the extreme preset then my guess is a driver issue / system issue. It is possible the performance mode is bottlenecked as 1680x1050 is a joke for a dual gup card like that. I'd test heaven and 3Dmark11 as they both scale quite well ( much better than Vantage )
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