nVidia GK106 GPU core - hidden cluster?

[Deanodarlo]

I've noticed there is no core view of the GK106 chip released by nVidia. They claim the GTX 660 uses the full chip.

However five clusters? Doesn't make sense. GK104 is eight, the GK106 would most likely be six however it may have performed too well to be fully enabled.

Do you think there is a hidden cluster, just waiting to be released in the future?

 

[SPBHM]

measuring the die size and comparing it to gk104 and the known specs wouldn't give and indication about that?

 

[Deanodarlo]

Probably, we should try and work it out! Anyboard good at Jigsaw puzzles and measuring?

To give an idea, GK104 is 294mm and GK106 is 214mm. So, the GK104 is 27% larger.

 

[TakeNoPrisoners]

Probably, we should try and work it out! Anyboard good at Jigsaw puzzles and measuring?

To give an idea, GK104 is 294mm and GK106 is 214mm. So, the GK104 is 27% larger.

Well that size would point to 6 clusters as 294mm/8 = 36.75mm per cluster and 36.75mm * 6 equals 220.5 which is very close to 214mm. However I know pretty much nothing about GPUs so take with a large grain of salt.

 

[Haserath]

Divide the transistors and you get GK106 is 71.75% of GK104. I would assume the transistor count doesn't scale linearly down due to the extras for interface and other stuff not scaling(making GK106 slightly more), so I guess it's really 5 SMX.

On second thought... They might just lie to come out with the same one later with "more" transistors.

 

[tviceman]

I doubt it has any cores hidden.

 

[toyota]

its 5 and if it was 6 then Nvidia would have said one was disabled. they always disclose the details of their chip and that stuff is never a secret. and I don't know why 5 is so hard to accept as GK110 has 15.

 

[Deanodarlo]

and I don't know why 5 is so hard to accept as GK110 has 15.

It's because this time nVidia have not released an actual picture of the internal core.

 

[notty22]

A graph of the die was released, a graph of GK110 also.

http://www.anandtech.com/show/5840/...gk104-based-tesla-k10-gk110-based-tesla-k20/2

 

[SPBHM]

its 5 and if it was 6 then Nvidia would have said one was disabled. they always disclose the details of their chip and that stuff is never a secret. and I don't know why 5 is so hard to accept as GK110 has 15.

it's probably true...
but GK110 can also have more than what Nvidia is disclosing at the moment....

GK116 could well be the same GK106 with the hidden units active, like gf104 vs gf114, but in this case nvidia never hid anything, it was always known that gf104 had in reality 384 "cores", or that GF100 had 512.

 

[tviceman]

A graph of the die was released, a graph of GK110 also.

http://www.anandtech.com/show/5840/...gk104-based-tesla-k10-gk110-based-tesla-k20/2

You know, that diagram of GK110 is so odd. Why would they not just put 8 SMX's units in each row? Why waste that die space, unless it's being taken up by HPC and compute logic.

EDIT: I realize it's just a diagram and not an actual die shot. Probably not indicative of how the chip layout and usage is.

 

[Deanodarlo]

Diagrams are great for showing what is in the chip, but a real shot of the GK106's internals is what's required.

I expect it would look something like this:

http://wccftech.com/nvidia-launch-gk106-skus-including-workstation-board/

Six clusters, not five.

Just for reference, a real GK104 core:

http://www.guru3d.com/articles-pages/gigabyte_geforce_gtx_660_ti_windforce_oc_review,4.html

No such image for the GK106.