Image Quality - Shader Model 3 Vs Shader Model 2

It's pretty common knowledge that ATI's current hardware does not support Shader Model 3, but with the limited number of games featuring this, the missing support is more or less a non-issue. Nonetheless, Far Cry does support SM3 with the latest patch so we'll be looking into this. Just to bring some of you up to speed, here's what our very own Scott Harness has to say about it:

Shader Model 3.0 is a combination of Pixel Shader 3.0 and Vertex Shader 3.0, and also includes the SM2.0, SM1.1 and of course the other previous Pixel and Vertex instructions prior to 3.0. Another addition to Shader Model 3.0 is Displacement Mapping, which is similar to Bump Mapping, although unlike with Bump Mapping where you merely get the illusion of a raised surface, Displacement Mapping will actually raise the surface.

The other big thing with Shader Model 3.0 is Geometry Instancing which is a method of copying objects that are rendered the same rather than rendering more than one object. For example, perhaps you have a forest full of trees in a game, and all the trees look the same. Rather than rendering each individual tree, Geometry Instancing will copy the first one and duplicate it for the others.

When it comes to current graphics cards, the GeForce 6 series cards support Shader Model 3.0, although ATI cards currently do not. However, in practice, Shader Model 3.0 currently doesn't bring all that much to the table in the way of either performance or image quality; you can render just as well with Shader Model 2.0b (supported by ATI's X700/X800 Series).

Far Cry Patch 1.3 offers support for Shader Model 3.0 and this will in some instances give you a slightly smoother instance of light rendering, especially visible on metallic surfaces that reflect light. You can also see it in action when looking at certain levels with water which will appear darker due to the way the light source is calculated into the pixel shader rendering of the water.

To enable SM3.0 in Far Cry you will need to set the game to 'Very High' settings and of course have a GeForce 6 series card. Alternatively, you can also use the console command -

\r_sm30path 1

Geometry Instancing will be enabled as part of SM3.0 with GeForce 6 cards but you can enable it for ATI cards as well.

For ATI cards, you enable geometry instancing in the Catalyst Control Center under the 'API Specific' tab, then start Far Cry and type in the console -

\r_geominstancing 1

Here are a couple screenshots using a 6600GT and X800XL:

SM 2.0B	SM 3.0

As you can probably see, there is virtually no difference between the two.

Overclocking

In the past, ATI owners had to resort to 3rd party applications to overclock their video cards. There is now a new version of Overdrive introduced with the X850XT-PE that can overclock the VPU core and memory independently of each other, either manually or automatically.

When allowed to overclock automatically, we reached a VPU core speed of 582MHz and 592MHz memory. The temperature reached 83°C during this time (benchmarking) but the fan still remained relatively quiet.

Doing things manually, we topped out at a core of 583MHz and 601MHz memory. We were able to squeeze another 2MHz out of the memory, but the system repeatedly crashed after getting to the Windows desktop.

Final Words

Looking back, let's see what we've learned about the ATI Radeon X850XT-PE.

Technology - Let's get this one out of the way. The X850XT-PE is nothing more than a X800XT-PE on steroids. There is nothing new to the table in regards to VPU features, and the X850XT-PE simply bumps up the frequency on the core and memory.

Benchmarks (Timedemos) - No surprises here as the X850XT-PE is definitely the fastest ATI VPU in their arsenal. On average, the X800XT-PE is about 5% to 10%, give or take a couple percentage points faster than the X800XT. Assuming you are lucky enough to grab an ATI X800XT-PE, the difference will be smaller. Basically, if benchmarks are your thing, the X850XT-PE is the fastest card ATI has to offer.

Gameplay (Real-World) - You'll be hard pressed to notice much of a difference here as both cards "felt" the same while playing. Doom 3 and Half-Life 2 were more or less the same in terms of gaming experience, but to be honest, UT2004 and Far Cry felt a bit smoother under the more hectic battles with less stutter and framerate loss. With the scenarios we chose (and the games as a whole in general), Doom 3 and Half-Life 2 are a little slower paced and unlike UT2004, you're not going to have 32 players shooting particle weapons at you at the same time. Ultimately, the X800XT did handle UT2004 and Far Cry with aplomb, but it felt smoother on the X850XT-PE.

Image Quality (IQ) - We didn't go to deep into this as we have in the past simply because there wasn't much to talk about. The X850XT-PE is on par 3D and 2D-wise when compared to their previous R300 and R400 series of VPUs. I know some of you are probably asking where are our NVIDIA results, and unfortunently due to time and availability, we do not have comparison hardware, but I did compare the image quality with a 6600GT (benchmarks were not provided because it's a different class of card) and there was virtually no difference in image quality that we were able to notice.

Noise - We felt it is worth mentioning here since the X850XT-PE marks ATI's first two slot PCI Express solution due to the oversized heatsink assembly. Compared to the ASUS AX800XT, the ATI X850XT-PE was actually the quieter card overall. We used ASUS as a reference as they used their own cooler, and it is far from silent when under load. The X850XT-PE is not silent by any means, but after the initial spin up on boot, the card is much quieter than even the fan on Intel's stock cooler.

Value - This is where things either favour the X850XT-PE, or do not depending how you look at it. If you're looking for the fastest PCI Express solution from ATI, this is it. If speed and IQ is paramount to your gaming needs, without forking over $1000 for a SLI setup, this will be money well spent. However, what if you already own a high-end card from either ATI or NVIDIA (we're talking X800XT/6800GT and up)? Truth be told, the X850XT-PE will not be worth your while as the performance gains do not warrant a new $500+ purchase. If you're still sitting on a Pre-2004 video card, right now the X800XT sits at , while the 6800 Ultra's low point is . The X850XT-PE card is currently at , so make your own judgment.

Availability - Unlike the X800XT-PE, the X850XT-PE should be a lot easier to find, but that may change in the coming weeks as ATI began canceling some of the X850 Series pre-orders. All hope is not lost though as we've seen availability online for ATI's card as well as offerings from 3rd party manufacturers. Basically, the card is there for you if you spend the time to hunt one down.

Pros: Fastest ATI card on the market, great image quality, surprisingly quiet.

Cons: Expensive, somewhat limited availability. Not a viable upgrade if you're sitting on current generation hardware.

Bottom Line: Provided that you can pickup the X850XT-PE, coupled with a fast system, you'll have a screamer of a gaming rig. You'll be a lot lighter in the wallet, but that's the price you pay for this level of performance.