R520 is a dual slot card

excerpt:

- Many sources who have seen one have confirmed that ATI's next generation card looks just like its previous Radeon X800XT PE card. The reference design implies that you will need dual slot cooling. Chip will be clocked incredible high and our sources implies that will end up much higher than 600MHz plus than we suggested before. Some of the cards have left ATI's headquarters but R520 clock speeds are not settled as it's a matter of yields. We know that ATI will be getting in for a hard launch sometime in September time, so it has to have the real hardware as soon as it launches.


Nvidia's G71 is also dual slot

excerpt:


- The "Faster G70", which is how the G71 is being called internally now, targets almost insane clock speeds. We have learned that several boards achieved a clock speed of 800MHz, which just goes to prove that tweaks being done in 110nm G71 core will make R520 tremble, and force ATI to respond with its 32-pipe R580 as soon as possible.