XSReviews has reviewed the Sapphire HD 4830 512MB Graphics Card
A quote from the article:
>> Sapphire HD 4830 512MB Review
With ATI continuing to dominate the top end graphics card market, they're releasing cards left right and centre, to get even a firmer grasp on the top end of the industry. Today I'm looking at their 4830 card, which promises some top performance with a reasonable price tag. Let's see how it does.
>> Sapphire HD 4830 512MB Review