The Inquirer today heard ATI has done it best to improve to R520's yields but that the firm cant do wonders.
According to their sources the R520 may follow the X800XT Platinum which was barely available at all. The R520 will be able to compete with the 7800GTX with its sixteen pipelines, but their will be availability problems.
The launch date of the R520 and R520 XT (which still hasn't got a definitive name?) appears to be the first week and first cards will be available a bit later. The R520 will be clocked at 500MHz and is expected to have a reasonable availability while the 600MHz R520 XT will be there but not in numbers. The memory of the R520 XT is said to be clocked at 1400MHz.