Matrox G400

The G400 is a video card made by Matrox, released in September 1999. The graphics processor contains a 2D GUI, video, and Direct3D 6.0 3D accelerator. Codenamed "Toucan", it was a more powerful and refined version of its predecessor, the G200.

The Matrox G200 graphics processor had been a successful product, competing with the various 2D & 3D combination cards available in 1998. Matrox took the technology developed from the G200 project, refined it, and basically doubled it up to form the G400 processor. The new chip featured several new and innovative additions, such as multiple monitor output support, an all-around 32-bit rendering pipeline with high performance, further improved 2D and video acceleration, and a new 3D feature known as Environment Mapped Bump Mapping.

Internally the G400 is a 256-bit processor, using what Matrox calls a "DualBus" architecture. This is an evolution of G200's "DualBus", which had been 128-bit. A Matrox "DualBus" chip consists of twin unidirectional buses internally, each moving data into or out of the chip. This increases the efficiency and bandwidth of data flow within the chip to each of its functional units. G400's 3D engine consists of 2 parallel pixel pipelines with 1 texture unit each, providing single-pass dual-texturing capability. The Millennium G400 MAX is capable of 333 megapixels per second fillrate at its 166 MHz core clock speed. It is purely a Direct3D 6.0 accelerator and, as such, lacks support for the later hardware transform and lighting acceleration of Direct3D 7.0 cards.

The chip's external memory interface is 128-bit and is designed to use either SDRAM or SGRAM. Matrox released both 16 MiB and 32 MiB versions of the G400 boards, and used both types of RAM. The slowest models are equipped with 166 MHz SDRAM, while the fastest (G400 MAX) uses 200 MHz SGRAM. G400MAX had the highest memory bandwidth of any card before the release of the DDR-equipped version of NVIDIA GeForce 256.

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