Post: The Graphics Accelerator that Changed my World
Twenty-four years ago, on a chilly, Autumn day in 1997, I drove to my local computer shop in southeast Michigan and bought my very first graphics accelerator. Up until then computer video games (Wolfenstein, Doom, Doom II) had been fairly simplistic graphically and any decent (Intel x486, Pentium) central processing unit (CPU) could handle the double-duty of processing game data and rendering graphics to the video card. That was all about to change with the impending release of Quake II from id Software and Unreal from Epic Games. These "next-generation" games were designed from the ground up to be as graphically realistic as possible. I wanted, more than anything else, to play these games and I knew that only a real 3D graphics accelerator would let me do that. The 3D accelerator to beat back then was the Voodoo card (better known as the Voodoo 1) from a small company called 3Dfx. The Voodoo 1 was a beast of a card and I would have gladly sold my little brother to get my clammy hands on one. Unfortunately, the price of a Voodoo card back then was well beyond my reach and I didn't have a little brother to sell. I had to come up with something else if I wanted to crack Skarj skulls in Unreal or kick alien butt in Quake II. That something else ended up being a diminutive Matrox M3D add-on card and it changed my life forever.
The Matrox M3D, like the Voodoo 1, was a true 3D graphics accelerator that did nothing else but crunch pixels and assist the CPU with the Herculean task of rendering 3D graphics on screen. Unlike traditional video cards of the time, the M3D and the Voodoo 1 had to be added to a computer via a separate PCI slot. However, the similarities between the two accelerators ended there. The Voodoo 1 might have been the biggest, meanest kid on the block but he was no where near the fastest. That title (short lived as it was) belonged to the M3D and its PowerVR PCX2 chip. The PowerVR chip and its 4MB of onboard RAM ran at 66 MHz on a 64-bit bus and pushed 66 MPixels/s. In comparison, the much beefier Voodoo Graphics chip featured 4MB-8MB of RAM, ran at 50 MHz, and pushed 50 MPixels/s over a 128-bit bus. How did a PowerVR based card which had half the RAM and half the bus width of a Voodoo 1 card manage to beat the later when it came to rendering graphics on screen? They did it with an unconventional technique called tile-based rendering. Anandtech describes tile-based rendering as a way of drawing 3D polygons on screen in a way that's faster and more efficient than the traditional "draw everything at once!" approach that was being used at the time.
"Rather than process one polygon at a time without knowledge of other polygons in the scene, a tile based renderer first groups polygons together in groups called display lists. These display lists allow a scene to be broken into smaller blocks, known as tiles, which are then rendered independently."
Essentially, the PowerVR PX2 displayed only what the player was seeing at the time and nothing else. The technique worked quite well and allowed PowerVR to produce low-cost alternatives to 3Dfx and Nvidia's expensive, power-hungry 3D accelerators. As time went on PowerVR found themselves in a battle that they knew they couldn't win. Their competitors quickly caught up and then surpassed them with sheer, brute-force speed and overwhelming public mind share. Instead of selling out or giving up, the folks at PowerVR shifted their focus from desktop 3D acceleration to the then developing mobile market. That decision, as silly as it seemed at the time, has served them well over the years. Apple included PowerVR technology in every iPhone and iPad device starting with the originals and only switching to their own homegrown GPU tech with the last few years. Still, the market for PowerVR is huge and I don't see that changing any time soon. You'll find PowerVR in smart phones, smart televisions, automobile infotainment systems, and even home thermostats. No one but Apple can compete with them when it comes to crunching pixels within severely resource-constrained environments. Apple and Nvidia might rule the high-end gaming, smart phone, tablet, and machine learning spaces, but PowerVR rules absolutely everything else. Somehow I think they're just fine with that.
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