Matrox G400

The Matrox G200 GPU was a successful product that competed with a variety of combined 2D / 3D accelerators . When creating the G400, the technologies developed as part of the G200 project were approximately doubled. The new chip received several additions, such as multi-monitor support, a 32-bit high-performance rendering pipeline, and new 3D features ( Embossed Texturing ).

The G400 is a 256-bit processor that uses the so-called DualBus architecture: two 128-bit buses, each of which is unidirectional and designed to transfer data between function blocks in the chip. Compared to one wider bus, this architecture reduces data transmission delays and increases the overall bus efficiency. ^{[1] The} 3D core contains 2 parallel pixel pipelines with 1 texture block on each, providing the possibility of double texturing in a single pass. Direct3D 6.0 acceleration is supported in hardware. The memory bus is 128 bits and is designed to use SDRAM or SGRAM .

Perhaps the most notable feature of the G400 was its ability to control two monitors to display one desktop. This feature, called DualHead, was an important advantage of the Matrox G400 over its competitors. DualHead capabilities provided not only the extension of the desktop, but also its cloning, and a special DVDMAX mode, which displayed a video overlay on a second monitor. However, contrary to the name of this mode, the G400 did not support hardware acceleration of DVD decoding. The G400 has partial support for the DVD video decoding process, but it does not perform the two most demanding process steps — inverse discrete cosine transform and motion compensation.

Matrox products have been known for their high quality analog output, and the G400 is no exception. The G400 has been a benchmark for quality for several years and far exceeded some of its competitors (in particular, NVIDIA cards up to GeForce4 ).

The G400 is the first Matrox accelerator compatible with AGP 2.0 4X. The early (REV. A) G400 boards actually only supported 2X mode, but the later versions (REV. B) were fully compliant with the AGP 4X and worked at a higher speed.

The G400 was known for its processor dependency in 3D, due to both its architecture and driver features, especially OpenGL ICD. Objectively, the processor was somewhat slower than the analogues on board competitors' cards. However, it was programmable, which could theoretically improve performance, but Matrox did not describe the functionality of this component.

As already mentioned, the G400 had problems with drivers. While Direct3D support was admirable, the OpenGL ICD driver was very poor. The situation was similar to what happened with the old G200: OpenGL instructions on the G400 were executed with the help of a wrapper , converting them into Direct3D calls with a serious loss of performance. A high-speed OpenGL driver, called TurboGL, was also released, but it was only intended to support several popular games of the time. Only in mid-2000, the G400 received a fully compatible OpenGL ICD, capable of providing high performance in most OpenGL applications.

But even despite the initial driver difficulties, the Matrox G400 was very competitive. 2D and Direct3D performance was more than competitive with NVIDIA NVIDIA Riva TNT2 , 3dfx Voodoo3 and ATI Rage 128 Pro . In fact, before the NVIDIA GeForce 256 , the Millennium G400 MAX was the fastest Direct3D accelerator.

Matrox stopped supporting Marvel G400-TV quite early, because there was no way to make the Zoran chip used for MJPEG hardware video compression fully functional in Windows 2000. ^[2] A stable WDM driver was never released, video capture was possible. but only based on VfW .

In the fall of 2000, Matrox introduced the G450 chip (code-named "Condor") as the successor to the G400. The G450 was primarily distinguished from the G400 by a manufacturing process reduced from 250 nm to 180 nm. This made it possible to reduce manufacturing costs, increase the number of manufactured microcircuits, correct the errors of previous cores, and add new functional blocks. The clock frequency of the core G450 remained at 125 MHz , as well as the usual G400. Tests have shown that the processor cannot operate at higher frequencies than the G400. ^[3]

Perhaps the biggest addition to the G450 was the second integrated RAMDAC , which made it possible to connect two monitors without using a separate digital-to-analog converter. The RAMDAC speeds were still different: 360 MHz for the primary, and only 230 MHz for the secondary. This meant that the primary monitor could operate at much higher resolutions and frame rates than the secondary monitor. The G450 also received native TDMS support, and thus DVI .

The G450 has been adapted to use DDR SDRAM instead of the aging SGRAM on the G400. This made it possible to simplify the memory bus to 64-bit without reducing the memory bandwidth at the same frequency. A 64-bit bus reduces the complexity (and cost) of the board. However, DDR has higher latencies than SGRAM equal bandwidth, so performance has slightly decreased.

The G450 received support for AGP 2.0 4X, as did the later G400 boards. The 3D capabilities of the G450 were identical to those of the G400, however, due to the same core frequency and lower memory bandwidth, the G450 in games was slower than the G400. ^[four]

The MGA-G550 processor received a second pixel pipeline, hardware geometry and lighting (T&L) processing, and hardware implementation of vertex shaders . It has 256 permanent registers designed to implement DirectX 8.0. Despite this, support for DirectX 8.0 in drivers was never implemented.

In 2005, Matrox Graphics introduced the Millennium G550 PCIe, the world's first PCI Express x1 graphics card . ^{[5] The} map uses the Texas Instruments XIO2000 Bridge. ^[6]

• FiringSquad's Review of Matrox G400
• last wayback archive of Matrox Guide to EMBM (Environment Mapped Bump Mapping)
• Matrox Millennium G450 at Digit-Life.
• Matrox Millennium G450 Review at Firingsquad.
• Matrox Users' Resource Center
• Tom's Hardware's Review of G400