ATI shipped most of the review cards with 8.364 driver the one that had some issues with performances and HDMI audio. In the meantime the driver got updated to 8.374 but this one was faster but buggy.
Not it looks like that ATI is working hard to ship the Radeon HD 2900 XT 8.38 driver as this one should bring even better performance.
A lot of partners decided not to send the samples as their cards are the same as the reference ones.
Published in Graphics
R600 8.38 driver to save the day
Even better performance