By: Nick Evanson Oct 29, 2007

Well, that's what this person is claiming (thanks for the link, Arathorn!), so naturally I decided to give it a bash. Have a look at what you actually get.

Basically, what is being claimed is that one can copy all of the system settings in the config files from the Very High section into the High section - in theory, allowing the DX10-only effects to be used in DX9. So let's see then:

Light beams through foliage

---

DX9 High Settings

DX10 Very High Settings

Water effects & HDR Lighting

---

DX9 High Settings

DX10 Very High Settings

Extra geometry & Parallax mapping on the ground

---

DX9 High Settings

DX10 Very High Settings

Certainly, some effects are carried across - for example, light beams from the Sun cutting through trees, as well improvements to the water and sky. For others, it's a bit hard to tell but one thing is absolutely certain though: you'll take another chunk out of your performance. Crysis, it would seem, is quite happy about making mincemeat out of any PC that you'd care to throw at it.

Please note that you're not getting DX10 on XP - all this is showing is that Crytek coded the shaders and effects for the Very High setting in both SM4.0 and SM3.0. You might ask, at this point, what's actually different, then? It was interesting to note that whilst using the "hacked" settings, the in-game menu listed all of the details as "High" bar the shader quality, which was "Custom." It could be the case that it's only the shaders that are really used but whatever the case may be, Crytek have got some explaining to do about why they've insisted that only DX10 was suitable for the Very High settings - sure it's still a performance killer in DX9, but that's not really different from DX10.

Edit: Having gone through the shader cache file in the demo, one can pick out the following shader files that is present in the D3D10 (DX10) set, but not in the D3D9 (DX9) one:

Vertex Shaders

_Shared@Common_ShadowGen_VS_DX10.fxcb
Particles@Particle_ShadowVS_GSPassThrough.fxcb
Particles@Particle_VS_GSPassThrough.fxcb
ParticlesNoMat@Particle_ShadowVS_GSPassThrough.fxcb
ParticlesNoMat@Particle_VS_GSPassThrough.fxcb
WetLayer@WetVS.fxcb

Pixel Shaders

_Shared@Common_ShadowGen_PS_DX10.fxcb
WaterVortex@WaterPS.fxcb

Plus there are the Geometry Shaders, which DX9 doesn't have anyway, which are to do with particles, shadows and stars. This suggests that there isn't a huge difference in the number of effects between DX10 and DX9 but since the shader code is not accessible, it's impossible to tell (certainly to my untrained eye) whether there's any actual difference between the common shaders.

Whatever the case actually is, these brief tests suggest that Crytek have almost certainly deliberately capped DX9 detail settings to ensure that DX10 can look as good as possible.