Reasonable guess for shader FLOPs on RSX would be?

[marconelly!]

Can someone give a reasonable guess of how many FLOPs RSX would be capable of (actual shader flops, not 'NVFLOPs' of course). Would it be reasonable to assume the shader ALUs in it would be the same as in NV40, just more of them? (24pixel, 8vertex). Is that actually the case with G70 as well?

 

[ERP]

I'm guessing next week, we'll have a better idea on G70. Although assuming it's a lot like NV40 I'm sure we'll be arguing how to count the free PP normalise's, and SFU's

I don't honestly know how RSX will relate to G70, if I had to guess, I'd say it will have a similar configuration, but I'm basing that purely on the fact that they have to get power and heat under control for the console and I'm assuming they'll use the drop to 90nm to do that. Of course this is nothing other than speculation.

 

[marconelly!]

Aren't SFU units used for some non-programmable fixed functions? How and where do they exactly come into play? Can you also clairify for me what is PP normalise?

Also, and perhaps unrelated, is it really true that G70 chip is supposed to have some speciffic optimizations for U3 engine, and if true, what those could be?

 

[ERP]

NV40 has hardware to compute verious bits and pieces in parallel with the shader ALU's. Sin, Cos etc these are the SFU's (Special Function Units).

The Partial Precision Normalise is the ability of NV40 to normalise a partial precision vector in parallel with the other calculations.

How you want to count these against a FLOP rating who knows.

 

[Titanio]

Also, and perhaps unrelated, is it really true that G70 chip is supposed to have some speciffic optimizations for U3 engine, and if true, what those could be?

This much is true. Back in late 2003, in fact, Epic confirmed at a NVidia meeting that they were working with NVidia on specific optimisations for UE3 in NVidia's next gen (beyond NV40). No idea what they are though.

 

[AlNom]

Wow... that kinda... Are they even implementing Ati specific stuff? At some point they might as well call it the nVidia Engine. Given all the licensees, it seems extremely unfair.

 

[ERP]

I'm sure they met with all of the IHV's.

We have no idea how responsive the IHV's were to specific features at this point.

 

[Carl B]

Unreal 3 optimizations are definitely going to be something that pays off for a generation or two on the video card front. Who could have guessed that it would be forming the base of so many upcoming games?

 

[Titanio]

They're very close to NVidia, but they've always been wide open about that. Anyway, they also stress they look great on ATi, so I wouldn't stress it too much. I guess we'll hear more from Epic after the G70 is unveiled, which might give a better idea of what they were looking for from, or worked with NVidia on.

(BTW, Epic termed it as "collaborating" with NVidia on their next-gen - which might suggest somewhat closer discussion and involvement than the norm. I'd believe it given their relationship, but Epic may just have been having a "look at us, we're so special!" moment.)

 

[AlNom]

It's not the looks I'm worried about, it's the performance