Voodoo 5
[Image:KL 3DFX Voodoo5 5500.jpg|thumb|250px|3dfx Voodoo5 5500 AGP]
The Voodoo 5 was the last and most powerful graphics card line that was released by 3dfx Interactive. All members of the family were based upon the VSA-100 graphics processor. Only the single-chip Voodoo 4 4500 and dual-chip Voodoo 5 5500 made it to market.
Architecture and performance
[Image:VSA-100 GPUs.jpg|thumb|250px|VSA-100 ICs, revision 220 and 320 shown]The VSA-100 graphics chip is a direct descendant of "Avenger", more commonly known as Voodoo3. It was built on a 250 nm semiconductor manufacturing process, as with Voodoo3. However, the process was tweaked with a sixth metal layer to allow for better density and speed, and the transistors have a slightly shorter gate length and thinner gate oxide. VSA-100 has a transistor count of roughly 14 million, compared to Voodoo3's ~8 million. The chip has a larger texture cache than its predecessors and the data paths are 32 bits wide rather than 16-bit. Rendering calculations are 40 bits wide in VSA-100 but the operands and results are stored as 32-bit.
One of the design goals for the VSA-100 was scalability. The name of the chip is an abbreviation for "Voodoo Scalable Architecture." By using one or more VSA-100 chips on a board, the various market segments for graphics cards are satisfied with just a single graphics chip design. Theoretically, anywhere from 1 to 32 VSA-100 GPUs could be run in parallel on a single graphics card, and the fillrate of the card would increase proportionally. On cards with more than one VSA-100, the chips are linked using 3dfx's Scan-Line Interleave technology. A major drawback to this method of performance scaling is that various parts of hardware are needlessly duplicated on the cards and board complexity increases with each additional processor.
3dfx changed the rendering pipeline from one pixel pipeline with twin texture mapping units to a dual pixel pipeline design with one texture mapping unit on each. This design, commonly referred to as a 2×1 configuration, has an advantage over the prior 1×2 design with the ability to always output 2 pixels and 2 texels per clock instead of 1 pixel and 2 texels per clock.
This is the first 3dfx graphics chip to support full 32-bit color depth in 3D, compared to 16-bit color depth with all previous designs. The limitation of 256px × 256px maximum texture dimensions was also addressed and VSA-100 can use up to 2048px × 2048px textures. Additionally, 3dfx implemented the FXT1 and DXTC texture compression techniques.
The VSA-100 supports a hardware accumulation buffer, known as the "T-buffer". When rendering to the T-buffer, VSA-100 can store the combined outputs of several frames. This mechanism allows for creation of effects such as motion blur and anti-aliasing. VSA-100 supports rotated-grid super-sampling anti-aliasing modes, with a maximum anti-aliasing level determined by the number of VSA-100 chips in the SLI configuration. One chip allows 2× AA, two chips allows 4× AA, four chips provides for 8× AA and so on. The RGSS method of anti-aliasing combines multiple samples of each frame, resulting in higher quality than the brute force ordered-grid over-sampling of ImgTech PowerVR, ATI Radeon DDR and Nvidia GeForce 2.
The chip implements a 128-bit SDRAM interface, again similar to the Voodoo3. Memory capacity and bandwidth is separately dedicated to each VSA-100 processor. While capacity is not cumulative across the entire card, bandwidth is effectively cumulative and thus a card with 2× VSA-100 processors has similar bandwidth to a single-chip graphics card using 128-bit DDR memory. Memory is clocked synchronously with the VSA-100 chip. Later, unreleased boards were planned to offer a 64-bit DDR memory design instead, in order to reduce board costs through lower complexity, while offering similar RAM performance.
Voodoo 4 and Voodoo 5 support MPEG-2 video acceleration.
While VSA-100 is an AGP 4× capable graphics processor, 3dfx did not implement AGP texturing.
The Voodoo5 did not offer next-generation DirectX 8.0 vertex and pixel shaders that would be found in the GeForce 3 and Radeon 8500, nor even DirectX 7 features such as hardware transform and lighting acceleration for vertices. Designed for scalability, it was nonetheless unrealistic for 3dfx to incrementally increase the number of Voodoo5 chips just to keep pace in performance with rival developments. Nvidia would further refine the GeForce 3's feature set into the GeForce 4 Ti to satisfy multiple market segments, as did ATI which derived the lower-cost Radeon 9000 from the Radeon 8500.
Models
Voodoo 4 4500
[Image:3dfx Voodoo4 4500.png|thumb|3dfx Voodoo4 4500 AGP]Released after the Voodoo 5 5500, the Voodoo4 4500 is the budget implementation of the VSA-100 product. It used only one VSA-100 chip and did not need an additional power connection. It was more expensive yet it was beaten in almost all areas by the GeForce2 MX and Radeon SDR.
Voodoo 5 5000
The unreleased Voodoo 5 5000 was to be similar to the 5500 but with half of the RAM capacity.Voodoo 5 5500
The Voodoo 5 5500 comes in three flavors: a universal AGP version with full sideband support, PCI, and the Mac Edition, which is only available for PCI, though could run in 66 MHz PCI slots. The Mac Edition has dual link DVI-D and VGA-A outputs, the other versions just have one VGA-out.In games, the Voodoo 5 5500 is able to outperform the Nvidia GeForce 256 and ATI Rage 128 MAXX, but was late to market and up against the new GeForce 2 GTS and Radeon DDR, both of which easily outperformed it.
Voodoo 5 6000
The Voodoo 5 6000 is the unreleased high-end product in the Voodoo5 line. It was to use four 166 MHz VSA-100 processors, each with its own 32 MB of 166 MHz SDRAM, resulting in the first 128 MB graphics card. Approximately 1000+ test cards were produced. Because the card used more power than the AGP specification allowed for, a special power supply called Voodoo Volts had to be included with it. This would have been an external device that would connect to an AC outlet. Most of the prototype cards utilized a standard internal power supply Molex power connector.With regards to performance, little was known until enthusiasts were able to get pre-release hardware and run tests on it. The results showed that the Voodoo 5 6000 outperformed the GeForce 2 Ultra and Radeon 7500, which were the fastest iterations of the GeForce 2 and Radeon R100 lines, respectively. In some cases, the 6000 was shown to compete well with the next-generation GeForce 3.
The precarious financial situation of 3dfx was a factor contributing to the 6000's demise. But even had 3dfx survived long enough to launch the Voodoo5 6000, the production cost would have likely hampered its competitiveness from a profitability standpoint. Due to being burdened with much redundancy and a complicated board, particularly 128MB of RAM, it was projected to have a US$600 price tag, considerably higher than the single-chip GeForce 3 and Radeon 8500 which achieved similar performance in their debut releases with 64MB. The Voodoo5 6000's omissions would be apparent for its price, since it did not have next-generation DirectX 8.0 vertex and pixel shaders that would be found in the GeForce 3 and Radeon 8500.
There were five revisions of the Voodoo 5 6000:.