R400/R500 guessing game

R400 is at .13u

R400 does not resemble any graphics processor to come before it.

-R300 is a F15E Strike Eagle
-R400 is a F117A Stealth Figher

 

But the question remains: which of those would win in a dog fight?

 

I hope that analogy doesn't go too far. F15's kill F117A in dogfights.

 

Hehe Only if it can find it. But the "F" moniker on the F117A really seems to be a misnomer (I have heard that it was supposed to 'throw off' any who found out the name back when it was still classified, though I suppose it may have more to do with the size of the aircraft than its capabilities), as the F117A has no air-to-air weaponry.

Regardless, it really does look as if Hellbinder is referring to the R400 as a deferred renderer. I hope not, as I still don't like the idea of fully-deferred rendering.

 

Well if my info is correct Hellbinder, you're going to strike out again on R400 8)

 

All this mysterious 'sourcing', gets a bit tiring doesn't it?

 

hrm, CMKRNL or HellBinder....

I wonder who's more right.

 

CMKRNL,

Lets hear it...

 

I seriously, seriously doubt it. in fact.. I can absolutly gurantee it.

Unless you have some inside info that the R400 is Not a F117A???
Or are you so shure that you even know what I mean by that.

and dont suppose that i am refering to what chalnoth is suggesting. That was him talking not me.

 

Yes.. The embedded memory for frame/z buffer had to be humongous. I mean, 1600x1200*32 with 8xFSAA
I dont see embedded memory for frame/z like in flipper would be a option for PC graphics cards in the foreseeable future.

 

Well, Embedded memory would be best-used as a large cache. I don't think it would help for basic texture filtering, but would be a tremendous help for intensive dependent texture reads. In more general circumstances, it would be even more useful as a frame buffer/z-buffer cache.

 

Come to think of it...

Perhps I should have used the Term.. *Fly by Wire*...

yes, thats much better.

 

OMG!

R400 is teh antigravity engine from Roswell!

 

One thing to remember about R400 is that its probably taping out about now. I think we'll gradually start hearing a lot more about this soon...

 

I have a feeling it will be a fairly conventional 16x1 IMR with a 256-bit GDDR-3-capable controller, clocked at ~600/600MHz.

The "special" part will be the VS/PS unit(s). I think that is where the big leap forward will be compared to current designs.

MuFu.

 

If that were to be the case, it would be a pretty considerable improvement over the R300.

We're talking about a fourfold increase in fillrate and virtually double the bandwidth without even considering the advances in the shaders. How many transistors would that be - 170m+, perhaps?

 

Since when weren't old cards 'fly by wire' in the first place?

My source tells me the R400 will feature a 'look down shoot down' cockpit package. Pulse doplar radar that can track 16 targets at once and engage 4. It will also be more manervourable than the NVIDIA S-37. 3D Thrust Vectoring engines is also incorperated.

 

What I wonder is if Mufu source saying "hybrid" and "adaptive" is right, even partially.
An "adaptive" architecture could pretty much mean the GPU can allocate power to either vertices or pixels. That has been widely speculated before.
An "hybrid" architecture, however... What the heck is that?

"hybrid" would mean it got a little of multiple worlds, and united it into one to make something which is potentially better than both. The best example would be a semi-deferred architecture.

Actually, there's one strange thing which might be called that. And it might give a lot of performance advantages, even more in such an "adaptive" case.
In current cases, front-to-back ordering saves rasterization work. However, you don't save *any* T&L/VS work! And in an architecture where those would basically be united, it would hurt both to do that.

So, the idea would be to determine X, Y and Z for the vertices. You do everything as usual, but don't do any useless color/texture/... work. You send that to Triangle Setup, and only determine which pixels/subpixels are inside the triangle. Then you do Hierarhical Z and Early Z.

If every pixel fails Early Z, you simply stop right there. If at least one succeeds, however, you send information BACK to the VS and compute all other things.

Basically, you potentially saved a LOT of work. It might still cost quite much if you use complex bone skinning ( you got to do it anyway to determine X/Y/Z ) , but it's still a lot less. And this can be called a semi-deferred architecture.

This approach is even better in a case where PS/VS is united. PS is generally more optimized towards several dozens instructions. VS, on the other hand, is a lot better with much more than that. So, since VS programs would be executed in two different places, it would be less instructions at once. And that means both become slightly more similar ( this isn't a major factor, however, and it would be excellent in traditional architectures too )

Wait a second... That's brillant! If ATI doesn't use it for the R400, I think I'm gonna steal the idea and try to sell it to nVidia But then again, I'm sure one of you people will say proof me it's stupid. Ah well...


Uttar

 

GDDR-3 capable, heh. In case of any surprises from nVidia, of course.

That doesn't mean they will definitely use high speed RAM. It might not even clock that high (I consider above 500 MHz "high" for the R400). I'm not sure ATI would be banking on 600 MHz...I think the 500 MHz of the GF FX is an aberration to correct for deficient (compared to the R300) design, and was an aggressive target even for the "Black Diamond" process. I don't see that changing with chips with even higher transistor counts than the FX (though ATI seems to be able to design for lower power usage at a given complexity and clock speed).

This does not mean that I think that ATI can't achieve 600 MHz, however.

Though, of course, MuFu is in a better position to know (is that 600 MHz guesswork, or based on info?).

 

Uttar, how is what you describe different than the Z buffer first pass as in Doom and as S3 claims for the DeltaChrome? Perhaps I am missing something.