Introduction

ATI's new X1900 XT 256 MB is designed to fit into the $300 video card segment which is bound by the X1900 GT on the lower end and the X1900 XT 512 MB on the upper end.
The only performance related change compared to the X1900 XT with 512 MB is just the installed memory, all other features remained the same.

Complete Specifications

Features

• 384 million transistors on 90nm fabrication process
• Up to 48 pixel shader processors
• 8 vertex shader processors
• Up to 256-bit 8-channel GDDR4 memory interface
• Native PCI Express x16 bus interface

Ring Bus Memory Controller

• Up to 512-bit internal ring bus for memory reads
• Fully associative texture, color, and Z/stencil cache designs
• Hierarchical Z-buffer with Early Z test
• Lossless Z Compression (up to 48:1)
• Fast Z-Buffer Clear
• Optimized for performance at high display resolutions, including widescreen HDTV resolutions
• Ultra-Threaded Shader Engine
• Support for Microsoft® DirectX® 9.0 Shader Model 3.0 programmable vertex and pixel shaders in hardware
• Full speed 128-bit floating point processing for all shader operations
• Up to 512 simultaneous pixel threads
• Dedicated branch execution units for high performance dynamic branching and flow control
• Dedicated texture address units for improved efficiency
• 3Dc+ texture compression
• Complete feature set also supported in OpenGL® 2.0

Advanced Image Quality Features

• 64-bit floating point HDR rendering supported throughout the pipeline
• Includes support for blending and multi-sample anti-aliasing
• 32-bit integer HDR (10:10:10:2) format supported throughout the pipeline
• Includes support for blending and multi-sample anti-aliasing
• 2x/4x/6x Anti-Aliasing modes
• Multi-sample algorithm with gamma correction, programmable sparse sample patterns, and centroid sampling
• New Adaptive Anti-Aliasing feature with Performance and Quality modes
• Temporal Anti-Aliasing mode
• Lossless Color Compression (up to 6:1) at all resolutions, including widescreen HDTV resolutions
• 2x/4x/8x/16x Anisotropic Filtering modes
• Up to 128-tap texture filtering
• Adaptive algorithm with Performance and Quality options
• High resolution texture support (up to 4k x 4k)

Avivo™ Video and Display Platform

• High performance programmable video processor
• Accelerated MPEG-2, MPEG-4, DivX, WMV9, VC-1, and H.264 decoding and transcoding
• DXVA support
• De-blocking and noise reduction filtering
• Motion compensation, IDCT, DCT and color space conversion
• Vector adaptive per-pixel de-interlacing
• 3:2 pulldown (frame rate conversion)
• Seamless integration of pixel shaders with video in real time
• HDR tone mapping acceleration
• Maps any input format to 10 bit per channel output
• Flexible display support
• Dual integrated dual-link DVI transmitters
• Dual integrated 10 bit per channel 400 MHz DACs
• 16 bit per channel floating point HDR and 10 bit per channel DVI output
• Programmable piecewise linear gamma correction, color correction, and color space conversion (10 bits per color)
• Complete, independent color controls and video overlays for each display
• High quality pre- and post-scaling engines, with underscan support for all outputs
• Content-adaptive de-flicker filtering for interlaced displays
• Xilleon™ TV encoder for high quality analog output
• YPrPb component output for direct drive of HDTV displays
• Spatial/temporal dithering enables 10-bit color quality on 8-bit and 6-bit displays
• Fast, glitch-free mode switching
• VGA mode support on all outputs
• Drive two displays simultaneously with independent resolutions and refresh rates
• Compatible with ATI TV/Video encoder products, including Theater 550

CrossFire™

• Multi-GPU technology
• Four modes of operation:
• Alternate Frame Rendering (maximum performance)
• Supertiling (optimal load-balancing)
• Scissor (compatibility)
• Super AA 8x/10x/12x/14x (maximum image quality)