Famous Graphics Chips—1999 Imagination Technologies Kyro

Almost the first GPU
Dr. Jon Peddie
Published 12/19/2023
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1998 was the high point in the PC graphics chip industry, and 47 companies were designing or offering graphics chips for the PC. The Internet bubble crested, and the PC graphics chip market hit 130 million units—more than the shipments of PC. That was because gamers, engineers, and programmers were installing two graphics add-in boards (AIBs) into their PCs for more power and to drive multiple monitors. It was an exciting and dangerous period, a major inflection point in the industry.

Advanced 3D capabilities were being added to graphics controllers. Hardware transformation and lighting (T&L) was introduced on AIBs as a graphics coprocessor and headed for integration into the graphics chip. DirectX 6 had just been introduced, but it didn’t support T&L or the new pipeline engine being called a shader. In the fall of ’97 the high bandwidth AGP bus was introduced.

The big names in the graphics chip market at the time were 3dfx, ATI, Nvidia, and S3. The second-tier companies were IBM (the former leader), Matrox, Number Nine, Rendition, Trident, and VideoLogic.

Simultaneously, the leadership in the console market was shifting, as was the workstation segment. In 1998, the Intel 486 was about to be announced with a built-in floating-point processor (FPP) and an extended pipeline. At the same time, SGS Thomson changed its name to STMicroelectronics (STMicro). ST, as it was known, was Nvidia’s fab partner, and would switch to being VideoLogic’s fab partner. Almost all the norms in the industry were changing.

By 1999, things were changing even faster. The Internet bubble was deflating, and venture capital for startups and existing companies looking for a second or third round dried up.

VideoLogic changed its name to Imagination Technologies in August 1999.

The population of companies offering graphics chips dropped to 31 as the Internet bubble crashed, and by 2000, there would only be 15 suppliers.

VideoLogic introduces tile-based deferred rendering

VideoLogic was founded in 1985 and was a pioneer in offering multimedia—audio, graphics, and video.

In 1992, VideoLogic launched the Trident Project to develop tile-based deferred rendering (TBDR). In 1994 the company created the PowerVR division and introduced its TBDR PowerVR architecture.

A graphics controller or GPU would normally draw polygons individually. Imagination used display-list rendering that batched polygons before rendering them. PowerVR’s TBDR would capture the entire scene before rendering it. Then it sorted through the image and identified any occluded pixels, rejecting them before processing. Figure 1 is a diagram of the TBDR pipeline.

Tile-based deferred rendering (TBDR) pipeline

Triangles are not sent in a specific order to the graphics controller. It is the z-buffer’s job to decide, at a pixel level, which triangle appears in front of others. This method requires a z-buffer with the same X-Y size as the screen.

The image is created on the screen in a thirtieth of a second or less so it to fast to watch, but if you could you’d see the image created one triangle at aa time. Watching the same image being rendered by a PowerVR controller the image would be filled in with tiles from the left to the right, and subsequent rows from the top to the bottom. By using that technique, Imagination eliminated the need for a z-buffer, which reduced memory bandwidth and costs. polygons were pre-sorted from back to front. Any polygons that were behind other polygons were ignored or deferred.

The deferred rendering procedure is also called chunking. It can improve rendering performance using advanced knowledge on how to aggregate requests for memory allocation. If, for example, a certain type of object was used in clusters of eight, instead of identifying and then freeing each one separately, which would require sixteen calls to the heap manager, a single call could assign and the array of the eight objects which would reduce the calls to just two.

The PowerVR PCX series

By the end of 1995, VideoLogic developed the Midas 3, it’s first chip in the PowerVR series. It included the Texture and Shading Processor (TSP—code-named TexAS), in addition to an Image Synthesis Processor (ISP— code-named Sabre) plus a PCI and memory bridge chip.

VideoLogic delivered its first integrated chip, the PCX-1, and introduced the brand PowerVR In second half of 1996. The primary target for the company’s PowerVR Series1 was arcade systems. In 1995, VideoLogic licensed its new graphics controller to NEC. To ensure priority delivery, NEC invested in VideoLogic and obtained 2.29% of the company’s shares.

The ISP was scalable, and two or four ISPs were used in arcade machines. The PC version uses a 3-chip structure with a single ISP and TSP configuration.

VideoLogic was hoping to supply graphics boards to the PC market and graphics chips to the arcade market. With NEC’s connections and backing, VideoLogic did well, especially in Japan. However, the PC market competition was intense and had a different culture, one that was based on price and supply and less on relationships.

But the volume of the PC market was much greater than the arcade market and growing rapidly, while the arcade market was slipping into a no-growth phase. PCs were replacing consoles in the home.

Seeing the opportunity in the PC market and its growth, and evaluating the other chip suppliers’ products, VideoLogic decided to launch the development of what could have been the killer graphics chip.

Figure 2. NEC/VL PCX1 block diagram

VideoLogic was successful is selling PCX-1 to PC suppliers like Compaq and Gateway and the leading PC AIB companies of the day such Matrox, Tsang Labs. Those companies’ marketing and brand helped VideoLogic get its name established in the PC market as a leading graphics chip developer.

Sega was planning its next game console, the Dreamcast, and in 1996, it launched two development teams, one in California and one in Japan. Several graphics chip companies competed to be the supplier. Several including Nvidia, which had a development contract with Sega, thought they had won. But The Sega design team in California dropped Nvidia and picked 3dfx. A few months later, Sega announced that the Japanese team had won (which everyone expected to happen) and they chose NEC’s VideoLogic chip.

Unlike Nvidia who just walked away, 3dfx launched a suit against Sega and NEC (with VideoLogic) about the use of 3Dfx’s technology. VideoLogic avoided the drama, leaving it to Sega and NEC to deal with it. The trial attracted media attention because of some personal attacks and insults. Later VideoLogic confirmed Sega chose NEC for political reasons, and Sega confirmed that 3dfx’s version had no place in the project. Sega concluded the trial by agreeing to pay a $10.5 million settlement to 3dfx.

The company, now called Imagination Technologies and developed the Highlander (code name) chip, the PowerVR PCI-2. They brought out the Neon-250 PC AIB based on the chip. The Neon 250 reviews were not favorable, approaching mean. One reviewer wrote, “The Neon 250 is a big fat blunder in the shape of a video card.”

Imagination then quietly stopped pushing it, concentrating instead on the next generation design. The design goal was to jump a generation of what other companies were building.

ST Micro PowerVR3 and Kyro

Development began in 1999, on the next generation chip—Kyro. It would hit the market just as the Internet boom was starting its decline but the PC graphics market was still growing.

Nonetheless, VideoLogic intended to reenter the PC market and in April 1999, it announced it would partner with ST Microelectronics.

VideoLogic would switch from NEC to STMicrosystems. ST Microelectronics said they and NEC Electronics would pursue different market sectors. Both would work on their respective PowerVR roadmaps. The NEC relationship with VideoLogic continued in other segments, most notably, VideoLogic’s lucrative casino and Pacheco arcade gaming machines business, as well as gaming console.

VideoLogic’s first two generations of graphics accelerators, Series 1, and Series 2 were licensed and manufactured by NEC.

VideoLogic announced it would develop and sell its Series 3 design, which were planned to be produced later that year. The uncertainty about the dates got mixed reactions from the industry.

“It clearly made sense to focus on the Dreamcast activity,” said Hossein Yassaie, CEO of VideoLogic. “From a planning point of view, we’ve retargeted that product to be more cost-effective.”

The Series 2 controllers ran at a respectable 125 MHz. Impressively, they provided a similar performance level to competitors with75-MHz controllers. The advantages in efficiency prompted ST to commit its graphics architecture of the future to VideoLogic, explained vice-president, and general manager of ST’s Graphics Products Division, Tim Chambers.

“If an architecture requires 200-MHz, large frame buffers, then that will impact the system cost on the desktop,” Chambers said. “Everything else equal, PowerVR is very good, even with the smaller 64-bit frame buffer interface.”

Yassaie in the announcement, “The market may likely see Series 3 parts from both NEC and ST, but with different feature sets and capabilities and for different markets.”

Chambers said he didn’t envision direct competition between the two companies, but he didn’t rule out the possibility either.”

“We still have a relationship with NEC,” said Yassaie.

He was still trying walk the line between two partners who might become competitors, and cited his plan of helping partners define products, as VideoLogic and ST had done. Although neither company would discuss the features or specifications of the Series 3 design, Chambers said the controller would be built in a 0.18-micron process.

When VideoLogic decided to go with ST it had an influence on Nvidia. Chambers, a dexterous affable, diplomat, said, the relationship with Nvidia had reached “a natural end.” ST assistance to Nvidia in fabricating Nvidia’s first chips had been critical in helping Nvidia get established. ST fabricated Nvidia’s NV1 to the very successful Riva 128. The prospect of working with VideoLogic over Nvidia must have been very powerful. Nonetheless, ST would carry on manufacturing the Nvidia Riva 128 as long as there was demand.

ST was attracted to VideoLogic partially because of its game console business which added volume Nvidia didn’t have. Chambers complimented VideoLogic’s architecture and the image quality off the Sega’s Dreamcast, and arcade systems like Naomi. Chambers appreciated the VideoLogic design that kept as much of processing as possible on-controller. That reduced the frame buffer size and bandwidth to the minimum.

“The relationship with STMicro,” said Trevor Wing, Imagination’s VP of Marketing, “is more than just a fab—they’re the sales channel.” Given STMicro’s experience with selling Nvidia’s Riva, the company will be the first to ship the Series3, and they have input into the design. STMicro has its own blocks and 250 nm experience, he added.

VideoLogic reorganized then in August 1999, changed its name to Imagination Technologies.

PowerVR3 STG4000 Kyro—2001

At Computex Taipei, in June 2000 Imagination announced the Kyro and the VideoLogic Vivid! AIBs. Kyro was powered by Imagination Technologies’ third-generation PowerVR3 chip, which ST marketed as the STG4000. But the AIB didn’t get released until 2001.

The 128bit STG4000 was a 2D part marketed as a GUI accelerator and had:

  • 2D operations performed in hardware, including line drawing and mono color expansion.
  • Three-operand ROPs.
  • Bitblock: transparency and stretching operations.
  • Clipping and Color expansion.

Imagination had redesigned the GUI accelerator’s architecture and expanded it higher performance dual-pipeline design for gaming capability.

Figure 3. Block diagram of Imagination Technologies’ Kyro chip

The chip was introduced with DirectX 8, and OpenGL1.1, but it only fully ran DirectX 6 features (and had some compatibility for DirectX 7). Versions with 64 MB were announced, as was an exchange program for PCX or Neon 250 cards, but it never materialized. Unfortunately, Imagination was unsuccessful in attracting any big-brand AIB suppliers.

PowerVR3 STG4500 Kyro II (circa 2001)

Doing a process shrink of the Kyro from 250 nm to 180 nm to make it the Kyro II. Allowed the clock rates and memory bandwidth to be enhanced.

The specifications for the Kyro II included:

  • Memory bus128-bit, up to 64 MBytes SDR
  • Controller clock175 MHz (synchronized with the memory)
  • Tile rendering architecture with 32×16 pixels tiles.
  • Two-pixel pipelines with independent texture unit.
  • Independent anisotropic filtering of textures, bi- and trilinear (up to 16 samples)
  • Full Screen anti-aliasing without increasing the frame buffer size.
  • Rendering of just visible textured pixels eliminating need to store depth values)— the fill-rate was equal to 350 million pixels per second.
  • AGP interface 1X/2x/4x
  • Blending up to 8 textures in a single pass
  • DVI interface
  • 180 nm manufacturing process

No hardware T&L block was not included.

The 3D chip had hardware capabilities such as:

  • Preparation of triangles and texturing with shading parameters to removing hidden surfaces.
  • Flexible DirectX7 vertex format, however there was no mention of DirectX8 support.
  • OpenGL ICD support.
  • 8-layer multi-texturing with unique features.
  • A DLR (Display List Renderer) mechanism to split the entire scene into separate sections.
  • Gouraud RGB shading and specular overlay.
  • Bilinear, trilinear, and anisotropic filtering.
  • Alpha Texture Blending and Color Dithering.
  • Vertex fog.
  • Texture compression.
  • Environmental Bump Mapping (EMBM), Perturbed UV Bump Mapping (aka Dot Product) and Embossed Bump Mapping.

Hercules Graphics was one of the first AIB suppliers to use the new chip . The company introduced its 3D Prophet 4000XT (Figure 4). It was a popular AIB, and it helped extend Hercules’ marginal existence.

Figure 4. Hercules 3D Prophet 4000XT 64MB PCI

Unfortunately, very few other AIB suppliers used the chip because it was seen as a stop-gap product. In 2001 it was the era of the GPU—competitors ATI and Nvidia, and others had added a hardware T&L engine.

With no internal T&L engine, Imagination had to rely on the floating-point processor in the CPU—the same as they did with the Dreamcast. Nonetheless, the graphics controller had some worthy capabilities such eight-layer multi-texturing (different from eight-pass), trilinear and anisotropic filtering, environment mapped bump mapping, and Direct3D 8.1 compliance— in the past the company had difficulty with DirectX compatibility. The Kyro II also offered full-scene anti-aliasing and could do dot-product bump-mapping at the same speed as Nvidia’s GeForce 2 GTS. However, Kyro II didn’t have cube mapping or legacy 8-bit palette textures compatibility, but it did have S3TC/DXTC texture compression.

Imagination and STMicroelectronics highlight Kyro’s 2D performance in addition to its 3D capabilities, video playback and DVD decoder support, but most of all they talk about tiling. The dispute in the industry has been given the issue of limited memory bandwidth, tiling technologies are more efficient at processing pixels than basic frame buffer—Graphics controllers employing tiling use less memory.

Tiling for 3D

Imagination Technologies and VideoLogic before them offered a graphics chip design with tiling technology, and they paid the price on the learning curve. During the confusing days of the API wars, engineers at VideoLogic’s struggled to ensure compatibility for its PowerVR products with various APIs. The company was luckily in having the NEC/Sega partnership which gave them a revenue for the PowerVR technology while they worked out the kinks for the general market. The Sega Dreamcast was a great advertisement for Imagination; it was proof of the value and economy of Imagination’s tiling design.

Despite its limited specifications and lack of hardware transform and lighting, the Kyro II was a highly functional part. Even competitor Nvidia acknowledged that. However, as games increased the amount of geometry, Imagination’s Kyro II lost its attractiveness.

Faded Dreams

A PowerVR4, Kyro III AIBD with a STG5500 chip was planned by Imagination for 2002whihc would include a T&L engine. A few protypes were given to reviewers to test. But STMicro had decided in late 2001 to exit the market and tried to sell its graphics division (which would include the PowerVR Series 4 and 5 licenses)—but it was not successful. In 2002 the company just closed its graphics division. Imagination couldn’t find a new fab in time and the product died.

In addition to T&L the new design had hardware sorted surfaces and 3D objects from the angle of vision and it removed invisible triangles before they were transformed or lit. The sorting and lighting of the 3D objects was in software—a concept that had been used in the driver of the previous Kyro AIBs.

Imagination decided to exit the PC AIB market and concentrate on IP licensing after ST shut down its graphics group. The company decided to expand their options and service the arcade and Sega’s game console market first; they were paying customers.

The End?

During the early 2000s other companies tried to develop tiling engines. In the early 1990s Imagination pioneered the technology in the PC and game consoles, and later the smart phone.,. Companies such as Gigapixel, Microsoft, and Stellar tried to bring out a tiling architecture. 3dfx acquired Gigapixel, Microsoft introduced its Talisman design (some companies said they would employe it but didn’t). and Broadcom acquired Stellar. In December 2000 3dfx went bankrupt; and Nvidia bought its assets, getting the titling technology. In 2015, Nvidia introduced tile its Maxwell with tiling, in 2016 its Pascal architectures. The Maxwell and Pascal GPUs employed immediate-mode tiling rasterizers. In lieu of conventional full-screen immediate-mode rasterizers the pixel output was buffered.

Kyro would be Imagination’s last foray into the PC graphics market and the company shifted to focus on mobile phones. The PowerVR design was the GPU inside many of the new all-screen devices that didn’t rely on a physical keyboard or stylus and used smooth graphical interface.

However, Imagination didn’t entirely leave the PC market. Intel decided to use Imagination’s IP GPU in October 2006 in its PC, mobile computing, and consumer processors; Intel also bought shares in Imagination.


history of the gpu part 2This is my 43rd article on famous graphics chips, beginning in July 2018.

I wrote a three-volume series on the History of the GPU, published by Springer, which can be found here: https://www.amazon.com/History-GPU-Steps-Invention/dp/3031109678 , here: https://www.amazon.com/History-GPU-Eras-Environment/dp/3031135806 , and here: https://www.barnesandnoble.com/w/the-history-of-the-gpu-jon-peddie/1141757660 which greatly expands the story of Imagination and most of the other suppliers and their history up to present day developments. And you can always contact me at jon@jonpeddie.com


Disclaimer: The author is completely responsible for the content of this article. The opinions expressed are their own and do not represent IEEE’s position nor that of the Computer Society nor its Leadership.


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