Guru3d - Directx 9.1 will boost NV3x PS2.0 by 60%???

g__day

Regular
I find this hard to accept simply at face value with no facts or analysis behind it...

http://www.guru3d.com/newsitem.php?id=637

From a major news source, Microsoft is, with the assistance of nVidia, about to release a new version of the great and essencial DirectX 9. And it will be Direct X 9.1. What's so amazing about this? Well, this new DX will favour nVidia's CPU's, especially regarding the pixels shaders 2.0. When accompanied by a regular update, the expected performances would be with the height of the unconditionnal hopes of the californian company. The perfomances in DX9 (for example HL2) would then be similar to those of the competition in terms of quality and especially in terms of speed. And all in precision mode of 32 bit in the PS 2.0.

Maybe a better management of the instructions of the PS 2.0 (improvement management of the streaming instructions ). To quantify, that could go to 60% of profit. A percentage that seems confusing and amazing but that we can't verify before it is released. All that we can say is if that is going to occur exactly as annouced, it will be an enormous relief for all the purchasers of GeForce FX.
Personally I'm in a state of let's wait and see before we can believe. But you have to admit that this is a really interesting turn of events.

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Very interesting supersition - but I don't see any hard facts backing this up.

Anomalies

Directx 9.1 is still unconfirmed by Microsoft - we don't know if it will ever be launched because its main features Vertex and Pixel Shaders 3.0 are already provided in Directx 9.0, obivating the need for a new version.

NV35 has too few full function 32 bit pixel shader pipelines and at present HLSL compliers optimise in a way that exposes NV35 register (and register combiners) shortages - causing pipeline stalls very frequent - which in turn cause a 60% loss of performance.

Half Life 2's 1,200+ shaders are apparently littered with partial precision hint to try and get NVidia off the 32 bit rendering path to try and boost its performance.

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My point of view - I'd rate the likihood of this being true at face value at < 30%. What may be true is NVidia within 3 months manage a 20% - 30% Pixel Shader boost by new shader optimiser routines in theirs and Microsoft's compilers for NV3x / DX9 and different texture management routines. Maybe this could be a new DX call it 9.1?

Also NVidia and Valve may find a way to kludge high dynamic range effects without requiring fp32, its just possible as a long shot
 
Doug Rogers @ NVidia said:
The floating point textures in the GeForceFX do not support wrap mode, nor MIP maps.

Not even wrap mode :oops:
That's one step more limited than I thought it was. And I can't make any sense of why it would be harder hardwarewise to support wrap on floating point textures.
 
It seems like floating point textures are not even done through the TMUs, but by direct memory reads. One possibility for NVidia would be to expose only a 512 instruction limit for PS and use some additional instructions for wrapping, but that would also mean a change in texture sampler state changes the shader in use.
 
Yes, adding a 'frac' before texture access should be enough for wrapping. Adding MIP mapping would be more of a problem. But hey, who'd notice if it doesn't really work? :)
 
Ostsol said:
Well, AFAIK NVidia's FP textures work in OpenGL. . .
Yes, but as TEXTURE_RECTANGLE_NV, which means:
no mipmaps
only plain 2D, no cubemap, no 3D map
no repeat or mirror, only clamp
no normalized texture coordinates
no filtering
 
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