"development name ATI uses for Xenon's graphics is "C1", whilst the more "PR friendly" codename that has surfaced is "Xenos". ATI are probably fairly keen not to use the R500 name as this draws parallels with their upcoming series of PC graphics processors starting with R520, however R520 and Xenos are very distinct parts. R520's aim is obviously designed to meet the needs of the PC space and have Shader Model 3.0 capabilities as this is currently the highest DirectX API specification available on the PC, and as such these new parts still have their lineage derived from the R300 core, with discrete Vertex and Pixel Shaders; Xenos, on the other hand, is a custom design specifically built to address the needs and unique characteristics of the game console."