Ati's new X1900
Architecturally, the X1900 is similar to the X1800, but ATI decided to throw in even more of the good stuff. Whereas the X1800 has 16 pixel pipelines and 16 pixel shader processors, the X1900 XTX comes with 16 pixel pipelines and an astounding (and baffling) 48 pixel shader processors. It also has a core that's clocked at 650MHz and 512MB of GDDR3 RAM clocked at 1.55GHz. All these numbers boil down to a card that's very fast, in specific ways.
The X1900 series has the same ring bus memory controller found in the X1800, and it is designed to minimize latency and scale up compatibility with the fastest graphics memory to date. The chip uses eight 32-bit memory controllers, instead of four 64-bit controllers, to increase memory accesses. ATI has also switched to a fully associative cache to increase memory hit rates. All of these memory changes help to improve frame rate performance at high-resolution, high-image-quality settings where memory performance becomes the bottleneck. Improvements in hidden surface removal by culling out pixels not in view will also increase performance.
Since the X1900 and the X1800 families share many of the same specifications--texture units, amounts of memory, and memory bandwidth to name a few--you could come to the conclusion that the GPUs share the same bottlenecks, and you'd be partially correct. Over the years, ATI noticed that increasing all portions of the GPU equally would result in wasted processing power. ATI noticed that in current games, video cards perform five times as many arithmetic shader operations as they do texture shader operations. As a result, many of the improvements (namely the 48 pixel shader processors) to the X1900 come in the form of vastly improved arithmetic shader operations. The improvements, in turn, show large performance gains in games that use complex shaders.
Another feature that made it from the X1800 to the X1900 is the ability to perform antialiasing on games that use high dynamic range lighting and Shader Model 3.0. Nvidia's GeForce 7800 series can render Shader Model 3.0 and HDR, but in certain games, you cannot enable antialiasing while doing so.
January 24, and this time around, i m inclined to believe them. Early reports from around the Web indicate that online vendors are showing availability, with prices at or below ATI's MSRP.
ATI's new X1900-'review'
Linear Mode
