(http://www.trustedreviews.com/)Review There's always been pretty heavy rivalry between ATI and Nvidia, but this time around it seems a lot more tangible. With both companies launching completely new parts at roughly the same time, it's understandable that there was a lot of pressure going around in both camps, writes Riyad Emeran.

By the time ATI was getting into the swing of things, Nvidia had officially launched the GeForce 6800, and speculation over which chip would be the fastest began to rise to fever pitch.

Early rumours about the R420 - the codename for the X800 - expected the high-end part to launch with 12 pixel pipelines, while pre-launch rumours about the NV40 - the codename for the GeForce 6800 - hinted that the high-end part would have 16 pixel pipelines. When the GeForce 6800 Ultra actually appeared it did in fact boast 16 pipelines, making the expected 12 pixel pipeline high-end part from ATI seem a little shaky. However, when ATI announced the Radeon X800 XT, it did turn out to be a 16-pixel pipeline part, putting it on level ground with the GeForce 6800 Ultra.

But the similarity between the ATI and Nvidia specs didn't end there, because ATI also announced that the Radeon X800 Pro would be a 12 pixel pipeline solution, just like the Nvidia GeForce 6800 part.

Let's cover the basics first. The X800 range of cards won't all be launching at the same time. So, today sees the launch of the X800 Pro (http://www.theregister.co.uk/2004/05/04/ati_ships_r420/), while if you want an X800 XT Platinum Edition, you're going to have to wait until 21 May.

As well as the 12 Pixel pipelines, the X800 Pro also sports six vertex pipelines, 256MB of GDDR 3 memory running at 900MHz, a 256-bit memory interface and a core VPU speed of 475MHz.

The X800 XT Platinum Edition on the other hand backs up its 16 pixel pipelines with six vertex pipelines, 256MB of GDDR 3 memory running at 1.12GHz, a 256-bit memory interface and a 520MHz core VPU speed.

As far as price goes, ATI has announced an SRP of $399 for the Pro and $499 for the XT part. Going out on a limb, I'd imagine that this will equate to British pricing of £299 and £399 respectively, although this is pure speculation.

Looking at the clock speeds on both the cards, you can see that ATI has really pushed the boat out, especially with the XT flavour. But amazingly, despite the higher clock speeds, ATI has managed to keep the power consumption to a minimum. Even the X800 XT card draws less power than the Radeon 9800XT.

The impressive low power consumption is achieved by the implementation of low-k dielectric technology. The low-k technology was first introduced on the Radeon 9600XT last year which showed off its low power consumption by not needing any external power. The problem with chip manufacture is that as the die process shrinks, the chances of interference and cross-talk between circuits becomes more likely. The traditional method of overcoming this interference is to push more power through the circuits, which will ensure efficient transistor switching. Unfortunately, more power also means more heat and you're left with a cooling issue too. But low-k dielectrics improve the insulation between the circuits, thus allowing efficient transistor switching without the need for excessive power, and consequently without the extra heat.

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Funny as it sounds, but it could be the low power consumption that makes the X800 a success. When you consider that the Nvidia 6800 Ultra draws a massive amount of power, it's not really an option in a small form-factor system. But the Radeon X800 XT will happily sit in an SFF box, and still push big frame numbers in all the latest games. Add to this that the Radeon X800 family of cards are all single-slot solutions, and it's clear that anyone wanting cutting-edge performance in a small system case is likely to go down the ATI route.

The decision to use GDDR 3 memory has cured any potential memory bottlenecks, allowing frequencies up to 800MHz (1.6GHz effective). The need for faster memory isn't something that's escaped Nvidia either, which is why you'll see GDDR 3 memory on the GeForce 6800 cards as well, running similarly high frequencies.

Physically, the Radeon X800 Pro looks pretty much identical to the Radeon 9800 XT. This is no bad thing, since it will obviously fit in almost any PC you care to throw it at. We probably will see a few custom designs, like we did from Asus with the 9800 XT, but most board vendors are likely to stick to the reference design.

As I've already mentioned, the latest generation hardware from both ATI and Nvidia look pretty similar (clock speeds aside). But, there is one major difference between the Radeon X800 and the GeForce 6800, and that's Shader Model 3.0 support. Now, this is where the marketing battle will be fought between ATI and Nvidia. Obviously Nvidia will be pushing Shader Model 3.0 support quite heavily since ATI doesn't have it, but how big an issue is this really?

Well there's no denying that there are some interesting features in Shader Model 3.0 that could potentially make developers' lives a little easier. For one, Pixel Shader 3.0 removes the 32 instruction limit, allowing for more complicated effects. Also, Vertex Shader 3.0 has the ability to create multiple instances of the same model with very little overhead, thus allowing more detailed environments to be created without causing too much performance degradation.

As far as Pixel Shader 3.0 goes, ATI argues that the same or very similar effects can be produced using Pixel Shader 2.0 and that's probably true. Where it does become an issue is when a developer wants to use more instructions than PS 2.0 will allow. For me, though, the best argument is not whether the same effects can be produced using PS 2.0 and PS 3.0, but rather whether we'll see many games using PS 3.0 to its full potential any time soon. It's all very well having hardware that supports the latest technology, but if nothing makes use of that technology is it worth having it? But then the other side of the coin is that it's better to have a feature and not need it, than to need a feature and not have it.

The Shader Model 3.0 debate is going to be a long one, and only time will tell whether ATI or Nvidia has got it right. Ultimately, it's in the hands of the game developers, so we'll just have to wait and see.

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If you've read this far, you're probably wondering when I'm going to talk about performance. Well, there is one thing that's true for both the Radeon X800 XT and the GeForce 6800 Ultra: you're going to have a very tough time finding a CPU fast enough to make the most of these cards.

To say that ATI and Nvidia have taken graphics to the next level with their latest chipsets is an understatement of epic proportions. ATI claims that the Radeon X800 XT is twice as fast as the Radeon 9800XT, which is a pretty amazing performance jump by anyone's standards. The only problem is that running a Radeon X800 XT in almost any PC available today, means that your graphics performance is limited by the speed of the CPU and not by the ability of the graphics card.

We tested the X800 XT using a 2.6GHz Pentium 4 'Northwood' chip and using a 3.2GHz Pentium 4 'Prescott' processor, both with HyperThreading. The former represents the average home system, where someone might want to upgrade their graphics card to get a bit more games performance. The latter represents a reasonably high-end system, but not a super-powerful setup where money is no object.

The 2.6GHz machine is exactly the same system that we used to test the Nvidia GeForce 6800 Ultra, so some of the scores are directly comparable. I say some of the scores because we only had the 6800 Ultra for a short while, so we could only run a limited number of tests.

Looking at 3DMark 2001 SE the X800 XT beats the 6800 Ultra at 1024 x 768 with no full-screen anti-aliasing (FSAA) or anisotropic filtering (AF). Pushing things up to 1280 x 1024 with 4x FSAA and 4x AF saw the 6800 Ultra edge ahead, while at 1600 x 1200 with the same features on, the X800 XT came out on top.

However, running AquaMark3 the 6800 Ultra managed to stay ahead of the X800 XT until we pushed things up to 1600 x 1200 with 4x FSAA and 4x AF, where the ATI card nosed ahead by a couple of frames per second.

Using Tomb Raider: Angel of Darkness, at 1024 x 768, the 6800 Ultra again edged ahead, but only by 2fps. While running X2: The Threat the numbers are equally close.

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Ultimately though, all these figures are not really showing the true performance of each card since the CPU just can't cope with the speed of these graphics chips.

We ran both an X800 XT and an X800 Pro on the 3.2GHz Prescott system, and the results showed that the faster CPU does make a significant difference. If you look down the graphs on the following pages you can see differences in the scores that equate reasonably to the differences in specification between the XT and Pro cards.

However, if you look at the graphs for the Far Cry benchmark, you'll see that even running a 3.2GHz CPU is severely limiting the performance of the XT card. Looking at Far Cry on the X800 Pro shows a steady drop in performance as features are turned on and resolutions are raised. But looking at the performance for the XT card shows that all the tests at both 1024 x 768 and 1280 x 1024 produced almost identical results. This means that the card is completely CPU limited, and it's only when the resolution is pushed up to 1600 x 1200 that you can see any deviance in the numbers.

Strangely, when we first ran Far Cry, there were some severe texturing problems, where dry land transformed magically into water at random moments. However, while I was waiting for ATI to get back to me with a fix for this issue, it cured itself with no intervention necessary. I'm not sure what caused this issue, but I am assuming that it won't be rearing its head when production boards hit the street.

It's clear to me that to fully test the ATI Radeon X800 XT and the Nvidia GeForce 6800 Ultra, you're going to need one of the fastest PCs on the planet. To this end, we're going to try and get hold of/build/steal/pray for such a machine and then get these cards back in the labs for some more tests.

One thing is for certain though, we have crossed the boundary of a new generation of graphics hardware, and this time it's not just marketing hype, it's the real deal.

The Radeon X800 is one heck of a graphics solution, and the fact that ATI has managed to squeeze this much performance out of a part that draws less power than its predecessor is a truly stunning achievement.

It's impossible to say whether ATI or Nvidia is going to win the graphics battle that's looming this summer, but for once it looks like the consumer is in a win-win situation. However, with the explosion in popularity for small form factor systems, that has to put ATI in a slightly stronger position as far as market share goes.

Verdict

Like Nvidia a few weeks earlier, ATI has managed to significantly raise the bar for graphics performance. The X800 XT is a blindingly fast card, but to be honest, there are few out there who'd be disappointed with the performance of the X800 Pro. All we have to do now is wait for production boards, and for the CPU manufacturers to produce something fast enough to get the most out of the latest graphics chips. ®

Related Reviews

Nvidia GeForce 6800 Ultra (http://www.theregister.co.uk/2004/04/14/nvidia_6800_ultra/)
AOpen Aeolus FX5900XT (http://www.theregister.co.uk/2004/02/10/aopen_aeolus_fx5900xt/)
Asus Radeon 9800XT/TVD (http://www.theregister.co.uk/2003/12/03/asus_radeon_9800xt_tvd/)

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