G71/G73: Summary & Pre-Launch Speculation Frenzy

With 18% core clock increase plus new drivers special sauce, this should beat X1900XTX.

And at like half the size apparantly.
 
mikechai said:
You forget ATI have special drivers too.
Click to expand...

Yes.

They both have highly secret spec units which get called on emergency when the terrorists appear or the competition has a faster part.
 
silent_guy said:
Hmmm. There's definitely a possibility that there are a number of excess units for redundancy. But an overhead of 33% (because that's how you should look at it!) is out of the question.
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[Sadly the 1337 mod skillz of one of our moderators, Vysez, meant that my follow-up post on this subject got moved out of context:

http://www.beyond3d.com/forum/showpost.php?p=712829&postcount=7 ]

I'd be interested in your interpretation of the following die shot (ATI's Xenos for XBox 360):

b3d34.jpg


I have coloured in what I think are the four shader arrays of this chip - each array appears to be split in two, either side of what I guess is scheduling/queueing/back-end type functionality.

Each shader array consists of 16 pipelines (rather than the conventional 4 pipelines that are normally considered to be a "unit" within a GPU). The texturing functionality of these pipelines is entirely separate as a single 16-pipeline unit - somewhere (I guess it's that big pseudo-symmetric block at the right of the die, just above MC0).

The chip is supposed to be around 232M transistors, and each shader array appears to consume about 8% of the die.

Finally, this GPU offers only 48 active pipelines - yet the design appears to consist of 4 arrays, each of 16. i.e. though architected for 64 pipelines, 16 appear to be dropped for redundancy.

In summary, only 8% of this die is consumed by shader array redundancy - if my theory is correct.

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So I'd be interested in your interpretation of the layout/redundancy of this die, which appears to use 33% redundancy for the pipelines - in total the four shader arrays consume about 33% of the entire die.

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As a matter of interest, at a guess, R580's fragment shader pipelines (if there are really 64, with 16 dropped for redundancy) would consume about 33% of the entire die: 128M transistors out of 384M.

Jawed
 
I don't think Xenos is good for comparison to any PC chip, having very different (simpler?) pipelines and some funtionality moved to that EDRAM chip. Or do you refer to the redundancy in the PS only?
 
Redundancy in the PS. Each shader unit is doing nothing more than arithmetic. Texturing is separate.

Jawed
 
OT: is there even any AF present in current XBox360 games or are my eyes slowly betraying me?
 
AF has to be applied correctly on consoles, i.e. by the developer. Actually being able to use sensible levels of AF is a new concpet for many console devs right now, so its probable that first gen titles aren't using it (take a look as some Test Drive Unlimited shots though, it appears to be applied on the road there).
 
Pictures from CeBIT.

Only the Asus 7900GT is somewhat larger heatsink covering the memory chips and is supposed to be $379. I guess better cooling solution, higher clocks equates a higher price tag for AIB versions.
 
Do the rumors about a different configuration of the TMUs in the G71, with regards to the G70, have already been discussed in the thread?

Because I thought that they were interesting.

Dave Baumann said:
Actually being able to use sensible levels of AF is a new concpet for many console devs right now, so its probable that first gen titles aren't using it (take a look as some Test Drive Unlimited shots though, it appears to be applied on the road there).
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That's OT, but since it's about Consoles...
All the consoles since the Dreamcast (or even the N64, for that matter) can apply different filetering to to the different surfaces of the scene. Le Man 24 on DC used AF for the sidetrack advertisement boards, for instance.
Also, activating a per surface filtering method is not complex from a code perspective, neither.

The IQ is up to the developers, some do not want to deal with the hit that AF comes with, other do.
Jawed said:
Sadly the 1337 mod skillz of one of our moderators, Vysez, meant that my follow-up post on this subject got moved out of context
Click to expand...
How clever of you!
If there wasn't 2 pages of an off topic discussion about R580 vs G7x in a 3 pages thread about the G71/G73, no thread split would have occured, don't you think. ;)
 
Jawed said:
Finally, this GPU offers only 48 active pipelines - yet the design appears to consist of 4 arrays, each of 16. i.e. though architected for 64 pipelines, 16 appear to be dropped for redundancy.
Click to expand...
The picture you have posted does not say that. Highlighting it differently leads to three very similar arrays. Alternatively, it is entirely possible that the pipelines in Xenos are still grouped into quads in hardware, and what you've highlighted are the twelve ALU's per quad.
 
Chalnoth said:
The picture you have posted does not say that. Highlighting it differently leads to three very similar arrays. Alternatively, it is entirely possible that the pipelines in Xenos are still grouped into quads in hardware, and what you've highlighted are the three ALU's per quad.
Click to expand...

Isn't that 12 ALU's per quad?
 
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