NV40 to support FP24?

volt

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Okay, a friend of mine -- owner of nvision.pl to be exact has just returned from CeBIT. Anyway, he talked to NVIDIA representatives and they told him NV40 will have support for 24-bit floating point precision amongst other things that were confirmed more or less. Below bit is translated (by me) from Polish:

"It's hard to get anything out of NVIDIA representatives. It is obvious they don't want to reveal any information about their next generation GPU. On the other hand, NV40 will premiere very soon and there is already a handful of information available. If you were to ask me about exact specs, I'd have to kill you. However I can always throw in some bits of information. It is worthy to look at current specifications (which were mentioned in our news section before) -- it is very similar to actual NV40 specs. NV40 will also sport hardware MPEG1 / MPEG2 / MPEG4 coding / decoding as well as support for 3D Shadows. NVIDIA has also reworked their 16-bit floating point precision usage -- FP16 and FP32 are said to work flawlessly now. Additionally NV40 will have FP24 support. The above information does look interesting. Did I mention, NVIDIA confirmed 16 pipeline architecture?"

While I talked to Polar about pipeline architecture, he could not confirm full 16 pipeline design. NVIDIA just told him it has 16 pipelines, they did not want to say more. Another important thing is that, NV40 will be widely available after the launch.

Now about R420. He also talked to ATI, but whenever he mentioned the chip, they started to talk about something else. One thing worthy to note is that new drivers will have a totally different look -- a more clean look. Also, ATI did not want to skip driver versions on purpose, someone just "messed it up" -- so no more skipping.

Please note that I did not say any of the above, so don't come after me. It's based on chat I've had with Polar.
 
Would it not be fair to say if you support Fp32 then by default you also support fP24. After all anything >= Fp24 is full precision.
 
Why would they bother to support FP24 if FP32 is supposed to be full-speed now? Sounds a bit like those Nvidia guys were BSing on purpose, I have to say.
 
I find that odd. If they're going to keep FP32 support, does that really make sense? I mean ATI used FP24 just to save transistors on calculations. They still store textures and framebuffer in FP32 format.

Maybe they converted their FP16 hardware to FP24, and they can output FP16 format like R300 can. Then they can use the faster FP24 whenever they want and the FP32 capability is still there. It still seems a bit silly to me, though.

Or maybe they'll make some demos that instantly show the drawbacks of FP24 :)
 
And, If nVidia now has FP24 support...... just what does that do to the FX...... lookks like we could have some serious orphans on our hands......
 
T2k said:
I don't understand something: if you have full speed FP32 and now FP24 why you need FP16? :?: :oops:

The prolem is that a FP32 chip can get very little performance improvement from using FP24 instead,someone correct me if I'm wrong.
 
T2k said:
I don't understand something: if you have full speed FP32 and now FP24 why you need FP16? :?: :oops:

Bandwidth. The same reason R300 can output FP16. Of course, calculations are done internally at another precision.

My guess is this is just a PR mistake, and NV40 does all FP calcs at 32-bit precision internally and writes out whatever format they want.
 
Mintmaster said:
T2k said:
I don't understand something: if you have full speed FP32 and now FP24 why you need FP16? :?: :oops:

Bandwidth.

Um, whaddya mean bandwidth? R3x0 with its internal 24-bit writes 32-bit pixels externally, so it's not neccessarily a bandwidth saving of any kind...
 
My bet is they just thought about full precision (FP32). I wonder about shadow volumes support: would it be possible to calculate silhouette and extrude it on NV40? (faster than on CPU?)
 
digitalwanderer said:
"We have now reached infinite improbability!" :oops:
What he said. It won't support FP24--doesn't make any sense considering their PS architecture.
 
UPO said:
My bet is they just thought about full precision (FP32). I wonder about shadow volumes support: would it be possible to calculate silhouette and extrude it on NV40? (faster than on CPU?)
Calculating the silhouette kinda has be done in software because not only do the edges have to be found, but new vertices have to be created to define the volume. Extrusion has been done via vertex shaders for quite a while, though.
 
I wonder why you would support FP24 is you can run FP32/FP16 flawlessly. I could have swore that one of NVidia's chief scientist state that FP24 was blasphemy.

Good little tidbit about a cleaner look to ATI drivers :D
 
991060 said:
FP16 and FP32 are said to work flawlessly now

Does it mean the register usage problem is gone or alleviated?
I guess I forgot that rumor. Yes, it has a hell of a lot more registers. I've heard one number for the amount of registers, but I haven't gotten any sort of confirmation on it. So, I'll leave it with yes, the register problem is at least alleviated and very possibly gone completely.
 
mreman4k said:
I wonder why you would support FP24 is you can run FP32/FP16 flawlessly. I could have swore that one of NVidia's chief scientist state that FP24 was blasphemy.

I just can't see them supporting it after all the FUD they pumped out against it over the last year and a half with their "cinematographantasmaorgasmic" talk that they'd just be opening themselves up for some HUGE attacks on their hypocrisy and screwing over the entire installed FX base. :oops:

Good little tidbit about a cleaner look to ATI drivers :D

No, it was an evil tidbit about a cleaner loot to ATi's drivers....it's going to keep me up at night wondering about it! ;)
 
Look, it doesn't support FP24. I've gotten a good amount of specific PS info, and it has no support for FP24. FP32/FP16.
 
The Baron said:
Look, it doesn't support FP24. I've gotten a good amount of specific PS info, and it has no support for FP24. FP32/FP16.

And let me guess, you're at school so me turning on Trillian would be a waste of my time. :rolleyes:
 
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