G70 has 32 pixel pipelines ?

[jerry]

With G70 now fully dissected we know have a little greater understanding of the part. Of course one element that characterises G70 is that of die size: its big.

Estimates of the die size put it in the order of around 330mm2, which on a 12" wafer would give in the order of around 150-170 full die to the wafer. Now, the issues here are one of yield - the fewer die there are on a wafer the more likely they are prone to defects. An analyst has suggested to us that there may be as many as 130-160 defects per wafer for earlier 110nm lines from TSMC (although the process is now more mature so that is likely to have decreased) which could give could potentially give very low yields for the chips should everyone need to work without any defects at all.

Now, one thing that we have been used to over the past few years releases is that of utilising defect cores in as lower performance products. The pixel pipelines, followed by the vertex pipelines, are taking the majority of the die space on products such as these and so a natural process defect is most likely to manifest itself in one of these areas; by disabling the pixel quad or vertex shader the defect has manifested itself in the IHV is then still able to recoup much of the cost of that particular piece of silicon, rather than wasting the entire die area.

The difference with G70 is that it is even larger than previous die sizes, which means that it is quite possible that full product yields may be quite small. Could it be that, in order to alleviate this, the defect rate is already built in to the current GeForce 7800 GTX and 24 fragment shaders is not the full number that G70 supports? Whilst many have speculated on an Ultra variant still to come and have been looking at the overclocks of the GTX’s to speculate where it may hit, perhaps it could be the case that there are 32 fragment pipelines in G70 and the fully working die are quietly being collected for use at a later date?

Source

This could mean Nvidia is selling the defective cores (those that dont have full 32 pixel pipelines) just like the 6800 vanilla but at a price point of $599. Anybody planning on buying the 7800GTX should hold off.

:whistle:

[Noveed]

lol hope they fix it soon :D

[jerry]

lol hope they fix it soon :D

586115727[/snapback]

It isnt "fixable" :p Just like all 6800s cannot be unlocked.

[Noveed]

oh bummer what about the different version of it? u reckon they all have the problem, if it has 32 pipelines or summit there cud be a possibilty of an overclock

[jerry]

oh bummer what about the different version of it? u reckon they all have the problem, if it has 32 pipelines or summit there cud be a possibilty of an overclock

586115785[/snapback]

That is exactly what Dave Baumann is hinting at; 6800 Ultra ?

[ANova]

Keep in mind that the terminology changes. Pipelines aren't straight pipelines like they have been in the past. The 7800 GTX has 24 fragment pipes with 16 ROPs, which means it can only output 16 pixels per clock.

[jerry]

Keep in mind that the terminology changes.  Pipelines aren't straight pipelines like they have been in the past.  The 7800 GTX has 24 fragment pipes with 16 ROPs, which means it can only output 16 pixels per clock.

586116616[/snapback]

Exactly, not a 'true' 24 pixel pipeline card in the traditional sense. I wonder how many people that bought this card actually know that. :laugh:

[Capodeluxe]

Exactly, not a 'true' 24 pixel pipeline card in the traditional sense. I wonder how many people that bought this card actually know that.  :laugh:

586116845[/snapback]

Better yet how many care?

[Noveed]

hey jerry you think the Ati x900 (r520) will be a true32 pipelines?

[sevastopol]

thay wont hav 32 pipes, coz 16 rops is definitely not enuf for 32 pipes

and apparently nvidia realised tht 16 rops arent the limiting factor as such for 24 pipes, dats y they decided not to increase it.

What GTX really needs is 512bit memory interface and faster ram - 1.4-1.6 gig

[jerry]

hey jerry you think the Ati x900 (r520) will be a true32 pipelines?

586117754[/snapback]

I dont know. From what Dave Baumann is hinting at, it probably is not a 32 pipeline card.

[ANova]

I dont know. From what Dave Baumann is hinting at, it probably is not a 32 pipeline card.

586118552[/snapback]

Nope. It will have improvements in other areas though.

[Argote]

I doubt this.... they may start implementing 32 pipe silicon when yieald are more mature and R520 is out (assuiming r520 in indeed faster than the current G70)