Time was, the PS2 was a Godsend. Up to 75 MILLION polygons per second, with all sorts of bells and whistles. An amazing "Emotion Engine" at the core of the hardware. Fully analogue control pads. DVD support. And a backwards compatible games library with the PSOne arsenal with improved graphics. Great, huh?

Well, almost immediately that 75 million polygons per second claim was revised down to 66 million. Then came another blow - these polygons wee flat-shaded, identical sized polygons with zero special effects. Suddenly this 75 million - or even 66 million - polygons per second claim looked rather shaky!

Sega, meanwhile, boasted a far smaller estimate: 3 million polygons per second. But what you may not know is that this number took into account 3D texture mapping, multiple size and positions and sizes of each polygon, multiple shading, anti-aliasing and more. So unlike the PS2, this number was EXTREMELY conservative. In fact, they were SO conservative that some games such as Le Mans 24 Hours actually pushed 5 million polygons per second, WITH all the special effects applied.

To be honest, the PS2 never actually pushed more than 2-3 million polygons per game. Silly factors such as a memory bottleneck (only a 4MB VRAM cache on its GS graphics processor) and an impossible architecture to programme for means that that potential of the Emotion Engine never got used. And also, to be fair, despite the claims made by Sony that the PS2 was a next step up from the Dreamcast, it only clocked in at 300MHz - the Dreamcast, over-clocked, weighed in at 240MHz, perhaps more. So there was far small a difference to shout home about.

In fact, even allowing for the memory bottleneck, thanks to the lack of special effects, when compared DIRECTLY To the Dreamcast specifications, the PS2 could only push 5 to 6 million polygons per second. And that's before you navigate the shifty architecture. It's no surprise that games such as Rez and Dead or Alive 2 look far better on the Dreamcast.

To illustrate the memory problem better, while the DC has 8MB of VRAM, the PS2 has only 4MB of VRAM. The main problem arises because a polygon takes up roughly 40 bytes of RAM. When you have 5 million of them in a given second, this amounts to 5 million/60fps = 83,333 polygons in a give frame of animation. If each of these polygons uses 40 bytes of VRAM, you will use 3.33 MB displaying these 5 million PPS. This doesn't leave the PS2 much room for it's framebuffer which uses around 1.2MB just to display the end data, not to mention that you still need to leave room for textures to put on those polygons.

There are more problems with the PS2. Even taking into account polygon shading, random mapping and special effects, we haven't touched on texturing. The PS2 has a terrible 4MB of VRAM whilst the Dreamcast had a more comfortable 8MB VRAM. And even then, a decent PC user will chuck thorough 32MB VRAM, usually 16MB. So how cam the Dreamcast compete, far less the PS2? The answer is that consoles do not hold all of a scene's texture data in memory at once. Usually, the data is streamed over the bus from main memory in a continuous manner.

The Dreamcast is a wonderful texturing beast, due in large part to the efficiency of the PVR2DC's graphics methodology. Two things help the PVR2DC - hardware texture decompression and infinite planes deferred rendering. Unlike the PS2's GS graphics processor, the PVR2DC is capable of decompressing textures on the fly. Thus, DC programmers usually take 20-25MB of texture data and compress it at a 5:1 (sometimes 8:1) ratio to reduce the amount of texture data to only 4 or 5MB. Then, the texture data is sent over the bus to the PVR2DC which simply decompresses the data at the moment of rendering into it's original huge size.

By contrast, the PS2's GS processor has no ability to decompress textures on the fly. This means that all texture data must flow over the relatively small pipeline between main memory and the GS 4MB VRAM cache, at it's original large size. Currently, this fact has limited PS2 games to only around 10 MB of texture data/frame, and this is why the buildings look so similar in Ridge Racer 5. Lack of variety in texturing has made most PS2 games look extremely plain when compared to Dreamcast games like Sonic Adventure, Shenmue, and even Draconus: Cult of the Wyrm.

Moreover, the PVR2DC belongs to the only processor family on the market that uses deferred rendering to texture only those polygons which are facing the gamer in any given frame. Other graphics chips must texture the backs of polygons as well as the front facing polygons. The net effect is to reduce the amount of texturing that the DC has to perform in a given scene by a factor of two or three depending on the complexity of the scene. The greater the scene complexity, the more you see the benefits of deferred rendering. This is why you never see any really large free-roaming 3D games on the PS2. Crazy Taxi, Ecco the Dolphin, and Shenmue are simply not possible on the PS2, because it doesn't have deferred rendering.

Now we must touch on the ease of development. The PS2 was a PIG to programme for, whilst the Dreamcast was a dream. The Dreamcast even featured Windows CE compatibility, meaning that games such as Quake could be ported with virtually no work. Additionally, the tools supplied to the developers was night and day. Sega furnished developers with excellent tools and documentation, whilst the PS2 developers were left to their own devices, with disastrous consequences. Unfortunately, key features that are very hard to implement, like anti-aliasing to remove jagged edges from on-screen polygons have not yet surfaced.

Developers have responded to these PS2 programming challenges in a number of ways. Some developers like THQ (Summoner) have used a form of CRT (Cathode Ray Tube) blending to fake the effects that true anti- aliasing would offer. This is something which the DC has had for over two years, but unlike the DC CRT method, the PS2 method results in washed out, blurry textures. Tekken Tag Tournament is the perfect US launch title example. While they have eliminated the jagged edges which plague the Japanese version, the end result is that all of the textures in the game seem blurry or washed out. Hardly what I would call revolutionary for a next-generation console.

Another developmental problem, which is the reason for the jaggies in the first place, is serious lack of kit functions that will intelligently enable developers to overcome some of the limitations of the small size of the GS VRAM cache. While all Dreamcast games run at 640x480 resolution, many PS2 games only utilitize a 640x240 field- rendered display which fakes a 640x480 display. Bad jaggies are the result, and these need to be hidden through some form of anti-aliasing (AA, not yet available), or by using the CRT method described above, with all its unintended consequences.

Moreover, the EE processor is actually three separate CPUs in one core. Most developers, for lack of proper tools, are using only one third of the EE's processing ability, because both vector units (VP1 & VP2) are too hard to program. Certainly future games will take advantage of these units, thereby freeing the main CPU to implement some fairly nice AI routines, but the cost of developing these techniques has become enormous - something which I will outline in the next article.

The sad fact is that only a few development houses like EA have been able to extract reasonable next-generation performance out of the PS2 architecture. Even Namco and Konami, the kings of PSX development during the 32 bit era, are having a hard time getting more than 2-3 million PPS out of what is supposed to be the end-all of gaming machines. The fact of the matter is that Namco's 18 month old Soul Calibur on Dreamcast looks worlds better than the newly released Tekken Tag Tournament on PS2. Not very impressive compared to the promises that have been made by Sony and it's cabal of industry sycophants.

So yeah. Despite clocking in at slower than the PS2, the Dreamcast TECHNICALLY is the better machine. It's why it outputs more polygons per second than the PS2 ever could. But the PS2 had other advantages. It had a DVD player which, at the time, was amazing - cheap DVD players just didn't exist. Even at a price point over £100 more than the Dreamcast brand new, the PS2 was STILL a cheap DVD player. And don't forget, the PS2 had a backwards compatible games library from the original PSOne library, a beast, especially when you count the fact that the graphics were improved upon. And the Dreamcast only had 1GB per disk to play with, meaning that some games such as Shenmue came on 4 disks, still clocking in at less than a single PS2 disk. But in terms of gameplay, the Dreamcast was the better machine, outputting superior visuals than the PS2 in like-for-like tests.

75 million polygons per second? Yeah, right.