We have already mentioned that both Shader Model 2.0b and Shader Model 3.0 are included and final in the 1.3 patch - we all remember the problems that lead to the withdrawal of the 1.2 patch. The different shader paths essentially improve the performance by reducing the number of instructions required to render the same scene, or do the same amount of work.
The shader paths are enabled by default on graphics cards that support the new shader model paths, so long as you select the 'Very High' in-game detail setting. You can, of course, force these shader paths using the in-game console; this is providing your graphics card supports the path you want to force.
To force the Shader Model 2.0b path input the following in to the console: 'r_sm2xpath 1' - this works on both ATI X800 and X700 along with all GeForce 6 series graphics cards.
As we already know, the GeForce 6 series makes use of Shader Model 3.0; you can force the shader model 3.0 path by inputting the following in to console: 'r_sm30path 1'.
The bug that we discovered previously has now gone, and there are no massive image quality differences between the two Shader Model versions, certainly not to the levels that were implied at the GeForce 6800 launch.
The water is slightly darker with shader model 3.0, and we think that it actually looks a little more realistic. Water is rendered using pixel shaders, and it would appear that they have made the pixel shaders slightly more dependant on the light source, which means darker water in this case. The water on maps, such as Fort, has not changed a great detail, which implies that the changes have been made for the darker sections of the game.
We have done a manual run through of the start of the Factory level, with a very small amount of time spent indoors, so we are seeing an outdoor frame rate here. Typically, indoor frame rates are higher than outdoors, as there are fewer objects to render using the vertex shader inside the GPU, which ultimately means less workload for the GPU.
It is very interesting to see that there are massive performance increases to be had when running the Shader Model 3.0 path - all in all, we have gained around 15% extra performance from applying the new patch. Where 1600x1200 with 2xAA 8xAF was not strictly playable on the GeForce 6800Ultra under patch 1.1, it is now playable with the use of the SM3.0 path.
There are no glaringly obvious image quality improvements for the Radeon X800 XT Platinum Edition here, but there are slight improvements in the water detail. These differences were apparent over the entire game - when we look at clear water, it's slightly darker. Again, we think that is down to the new shader path, which improves the quality of the reflections on the water's surface, and makes them more dependent on the surrounding lighting.
It is interesting to see that ATI's Radeon X800 XT Platinum renders water in a completely different way to NVIDIA's best, the GeForce 6800Ultra. The water isn't quite so dark on the ATI board; we'll leave the decision of which looks better up to you though, as image quality is always very subjective.
The performance differential here is not quite as great as what we see on the GeForce 6800Ultra, but it proves that Shader Model 2.0b has its performance advantages. The optimal settings and resolution that deliver 'best playable' circumstances for the X800 XT Platinum Edition remain the same at 1600x1200 with 2xAA 8xAF and, of course, maximum game details.