This week ATI sent an advisory out to its OEM partners announcing the details of the new Radeon X1950 and X1900 graphic cards. Both of these new cards are based on the same R580 core, but with some fundamental differences.
R580, the 48 pixel-shader processor version of the R520 (Radeon X1800), was announced this past January. R580 features a robust memory controller capable of utilizing several different types of memory, including GDDR4 which was not even available when the Radeon X1900 was first announced. Since then Hynix and Samsung have both jumped on the GDDR4 train with revenue shipments beginning several weeks ago. The new GDDR4 variants of R580-based Radeons are now called Radeon X1950. Radeon X1950 will retain all of the features of the Radeon X1900, and really only have the added benefit of a new cooler, GDDR4 memory and different frequency clocks.
Radeon X1950 at launch will come in two flavors: a high clock "XTX" version, and a CrossFire version. Both cards feature 512MB GDDR4, and the only major difference between the two is that the CrossFire X1950 houses the composite engine and input interfaces for CrossFire. Just yesterday, ATI issued an advisory to its partners claiming "Clock frequencies for RADEON X1950 family products are pending and will be provided at a later date." However, in March of this year ATI released a new policy for AIB partners to overclock X1000 series cores with some discretion. While we can already confirm some partners are planning 650MHz core versions, there is still a distinct possibility that higher clocked cards are also in the works. Memory clock frequencies have not been announced either, though Samsung announced its GDDR4 is already capable of 3.2GHz in 8x512Mbit configurations.
The new Radeon X1900 is a low-cost version of the existing Radeon X1900 that only uses 256MB of GDDR3, enabling the card access to the $300 price point. The Radeon X1900XT 256MB will use the same clock frequencies as other Radeon X1900XT cards: 625MHz core and 1.45GHz memory.
ATI's advisory documentation claims the Radeon X1950XTX will begin sample availability on August 7, with the CrossFire sampling beginning exactly one week later. Sampling of the Radeon X1900XT 256MB will begin immediately.
Radeon X1900 and X1950 will be replaced by another ASIC core, dubbed R600. R600 is expected to be 80nm with new design features above and beyond the R520 and R580 series.
. Looks like AC Silencer inspired cooling 
.