The ATI R600 Rumours & Speculation Centrum

Curious - can you explain how a memory choice would affect the release timings?

 

Did you care to look up Inq's history of G80 predictions? I would take anything they say with an enormous grain of salt.

 

Curiously or not, the ATI R600 "external 512bit memory bus" rumour started spreading right after the 384bit bus of the G80 was nearly confirmed.

Some jealous pro-ATI post around the web reaction can't be excluded from the list of possible origins, until there's more (and credible) evidence of the fact.

 

Predictions, Predictions, Predictions, Predictions....
We know squad about ATI R600: Only assumptions.

But my personal logical guess that sounds realistic at the moment is external 256bit wide bus over higher Speed 2.6-2.8GHz GDDR4 256bit. (Maybe lower speed on 384bit bus)

As far as ROP's; ATI could also follow Nvidia using only 24 ROP's. It could be 32 ROP's.

96 pixel shaders or 128 pixel shaders makes logical sense, but as far real 64 physical pipelines using 2:1 ratio to reach 128 shaders I'am not sure about that. I was thinking more like 32 pipelines using same 3:1 ratio to get to 96 pixel shaders. Just like R580 16 pipeline 3:1 ratio gets 48 pixel shaders.

Texture Units on R600 vs. R580 which is only 16. - it is possibility they could double it. - Since that is how generations of video cards usually goes.

 

Actually it was about the same time as the first G80 specs leak if i remember correctly.

I dont see ATI touching that type of ram. For one thing its still rare meaning low production and high costs.

 

So; your personal guess, where does it leaves you with your assumption?

 

Havn't we heard GDDR4 yeilds are extremely good? 1400mhz (2.8) is readily available from Samsung, with 1600mhz (3.2) looming extremely soon in the future. 2.2-2.8 (1.2-1.4ghz bin) sounds like a logical possibility to me, as we've seen stranger things happen (like nvidia using 1.1ns GDDR3 before it was readily available) and as we know cards are not usually clocked to the max of the binned chip used.

 

Hi Shtal,
you seem to be very knowledgable about these things (so much so, in fact, that you remind me of Ludwig Wittgenstein) and I have a few questions:

• What's an internal memory controller?
• Why is it useful to have an internal 512-bit bus when the external bus is only 256 bits?
• Why would R600 need a 512-bit bus to outperform the 384-bit bus of G80? Are the memory controllers of R600 less efficient?
• How is yield of R600 correlated with performance of G80?
• Why would the speed for 384-bits be lower than for 256-bit? (And wouldn't that require a 786-bits internal memory controller?)
• How many additional pins do you need for a 512-bit bus? And how much more expensive would the package be compared to the cost of the die?

Thanks!

 

What's the catch?

I will answer for now just one question at the moment first for you.
ATI does not need 512bit memory because?
a: to expensive
b. not sure what they would need it for all that extra bandwidth that could wasted completely.
c. If you look at Geforce 8800GTS, you simple overclock the core and you are getting GTX level of peformance of FPS without extra bandwidth needed.
d. 512bit my personal guess to early for now.
One more thing I want to add to this question on ROP's Between G8800 GTX vs. GTS which is 24 vs. 20 so far I could tell makes very small impact for now.
For the most part extra bandwidth start playing important role when you crank up resolution and enable Anti-aliasing (AA) or if you add High Dynamic Range (HDR) on top.

 

http://www.beyond3d.com/forum/showpost.php?p=871045&postcount=359

 

What do you think?

 

Doesn't it become harder to put more pins on a chip when it is shrunk.

 

http://ati.amd.com/developer/brighton/05 Graphics Performance.pdf

Seems like R600 will see more functionality of the drivers moved into the chip.

 

What can we glean from p20? R600 or R580?

 

I was thinking about availability of the specific memory of course. But since you know that very well, so I'll take the liberty to assume that the memory choice isn't an issue regarding the delay of the R600.

 

GDDR4-based graphics boards have been shipping in quantity since late August. That would indicate sampling some time before that (a quarter at least, one presumes) and MP of all variants is in full swing (at Samsung at least). R600 definitely isn't around just now because of the memory choice.

 

Yes, I am aware that the X1950XTX is using GDDR4 and it has been shipping for some time already. But that doesn't mean that there couldn't have been supply issues. nVidia after all decided to bypass GDDR4 for the (short) time being with the G80 and who knows if Samsung could ramp production enough for both X1950XTX and R600 for Christmas? I didn't know hence my supply speculation, but that is now lain to rest.

 

Take a peak on the G80 and tell me if you can compare it's TMUs with it's ROPs. In other words G7x TMU or ROP != G8x TMU or ROP and last but not least Vec16 ALU != Vec5 ALU. It was merely an observation for your collection of random numbers.

It could easily be a 6* 16-way SIMD with 24 TMUs and 16 ROPs. But that still doesn't say zip, zilk, nada since I cannot know what each unit is capable of. What's even worse are any kind of weird comparisons with what seems to be a fundamentally different design (G80).

 

I'm absolutely convinced at this point that we'll see R600 released to the public in 2007. However your supply considerations are still valid, should the first R600-based products be in volume production ready for Vista's consumer release (the likely release date IMO), but I think Samsung have plenty. If you ask them they say that GDDR4 supply is 'very healthy'.

I bet good money that it definitely isn't but I agree with you that unit counts don't mean jack this time around.

 

it's seems weird but i have this strong feeling inside me !!
we will see another nv30.But this time by ATI R600.it's the same
statution !!! new architecture new bus new direct X several delays by ATI.
what do u think guys ?!