TrustedReviews posted a review on the Sapphire HD 2900 XT 1024MB DDR4 video card

It seems ATI made the right decision when it chose not to ship HD 2900 XTs with 1024MB of memory. While doubling the memory quota does improve performance by a small margin, it is nowhere near enough to justify the increase in cost the extra memory would have demanded

Sapphire HD 2900 XT 1024MB DDR4 Review