It seems to me the most likely description of the NV34 is PS 2.0-alike non-fp16/fp32 capable fragment shaders (i.e., NV30 with the fp fragment processing units removed, among other things...though I still remain very curious about my vertex/fragment processing unit sharing tests).
This would be more functional than PS 1.4, but slower than PS 1.4 hardware when acting like it, i.e., as discussed about the nv30 being fast for 1 texture load (0 phase levels, PS 1.1-alike) but being equally slow for each additional dependent texture load as a tradeoff for the "Cinematic shading" (i.e., being faster for shaders too complex for gaming...though it would seem to behoove them to focus differently for the mainstream part).
This is something that Cg could expose and that DX 9 HLSL could technically expose as well, but it seems it won't because the intermediate LLSLs do not expose the possibility (PS 2.0 includes the expectation of floating point support AFAIK).
As we've mentioned before, this situation would also be reflected somewhat in the NV31 if it only supports fp16.
IMO, barring any nasty surprises, this doesn't make them bad parts (in contrast to, for example, my opinion of the GF 4 MX in the context of shader adoption), though the NV34 seems likely to suffer from what I'll call "Radeon 9000 disease"
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Based on these theories:
Things should still be fine for nvidia in OpenGL, regardless of Cg adoption...in the HLSL atleast. I also have some thoughts floating around about how Microsoft's IP declarations may relate to nvidia's efforts to establish Cg independently.
Nvidia's root problem, IMO, was in the apparent arrogance of their stance on Cg...the success of their design (the theoretical NV34, and maybe now NV31, design descriptions above) outside of OpenGL seems to depend on gaining popular support for Cg, and they seem to have assumed that their position as market leader at the time would allow them to mandate its acceptance by themselves. This would make their delay of the NV30 to boost clock speeds seem even more disasterous to me, as this would seem to have impacted their market share position even more negatively than being perceived to have lost the performance leadership would have (though OEMS, game developers, and game publishers who try to influence developer baseline targetting, may each have unique perspectives on the issue).
This type of arrogance may also be reflected in their decision to design their hardware regardless of standardization (the ever-popular glide comparison, except that there are standards now unlike when glide was first offered), but maybe it was just engineering ambition and arrogance just came into the picture in their approach to fitting the resultant design into the marketplace (as they seem to have tried instead to fit the marketplace to their design). At this time, my own opinion of their past behavior and comments such as those Richard Huddy have made make me think the former.
Also, their "pride" (or, less emotionally, their marketing dependence) in "performance leadership" seems to have been a big factor in their problems (though the proportional impact in the marketplace isn't necessarily accurately represented in a forum like this one), though maybe the NV35 and rumored R400 delay will change the picture later this year.