The core on the X1950 XTX almost remains unchanged running at the same frequency as the x1900- 650MHz. ATI does say that the core is tweaked and thus the model number has changed from R580 to R580+ and from our talks with ATI, that + sign is basically an updated/tweaked memory controller that will also take over the x1900 series in the future.

[NLN=ATI Radeon X1950XTX Review]http://www.tbreak.com/reviews/article.php?id=468[/NLN]