We reported some months ago that R520 will have up to 300 million transistors but it turned out that ATI manage to squeeze even more transistors on its die. This leads up to the fact that it's very likely to have more pipelines than in the current generation. Last number was 16 and now it's time to go toward 24 we would speculate.Read more at The Inquirer
ATI's R520 to have 300-350 million transistors

Some more details about ATI's R520 have been posted on the web. It is said that this 90nm core will have up to 300 to 350 million transistors.