ATI Radeon HD 4000 Series discussion

[Extelleron]

I am not believing all this just yet, but I would love to ATI pull an R300 out of the bag with the GTX going the way of the 5900

I do doubt the 800 SP rumours because 800SPs increases the die size dramatically, and since the process is the same as the 3870, we know that doubling the TMUs and more than doubling the SPs would be next to impossible without having a gigantic diagonal 90nm R600 size die:



As we have already seen the Rv770 die size and we know that the die size is only 50% larger, the 50% more SP theory (480 SPs) sounds more practical.

Those are my 0.02.

Perkam

As I've shown before, die size & processing resources do not scale linearly at all.

Case in point, RV635 (55nm/118mm^2) -> RV670 (55nm/192mm^2)

ATI fits 2.66x SPs, 2x TMUs, 4x ROPs, increased cache, plus twice internal ring bus size (512-bit vs 256-bit) in a die only 63% larger.

So it is not unlikely they can fit 2.5x SPs/2x TMUs, with all else the same, in a die 34% larger.

Comparing RV620 & RV670 just exaggerates the point.

RV670 is approximately ~3x RV620 and it features 8x SPs / 4x TMUs / 4x ROPs / 4x ringbus (512-bit vs 128-bit) / vastly more complex cache structure.

[eric66]

does anybody know anything about 3950 ?

[Extelleron]

does anybody know anything about 3950 ?

The Gigabyte placeholders are pretty much the only thing we have seen of the HD 3950.

It's most likely a RV670-based part with higher clocks than the HD 3870. I suppose it could be a chopped-down RV770 part, but I doubt it would be considering it is a HD 3000-series part.