We just received news that internal roadmaps from ATI have revealed more information about R590.  R590 will launch at the beginning of March for $279 (depending on vendor).  The R590 ASIC is effectively the Radeon X1900 core, but at a lower clock speed with some disabled features -- the roadmap did not state exactly what has been disabled. Expect to see the card retail as the Radeon X1800 GTO. The roadmap revealed that these cards will come with 256MB of memory.

Radeon X1800, the R520 ASIC, was a large disappointment for opponents and proponents of ATI alike. R580 was a much better GPU but, like NVIDIA's similar offerings, is very expensive.  The $250-300 price point has always been one of the most neglected price points for the GPU market.

A year ago, ATI used a very similar tactic by labeling R480 and R423 ASIC as Radeon X800 GTO video cards.  Several clever users were able to use BIOS hacks to unlock the disabled pipelines on these cards.  This may not be possible with the X1800 GTO as it uses a dedicated R590 ASIC spun specifically for these card models. 

The same source also indicated that 80nm R600 would be available this October.  Details beyond that are still light.