Larrabee Die-Shot - Analyze this

CarstenS · 12-May-2009, 09:54

Today, intel showed the first detailed die-fotograph of Larrabee - some pictures are to be seen at PC Games Hardware.

http://www.pcgameshardware.de/aid,68...fikkarte/News/

Some of the functional units can be distinguished also - pleases take your guesses as to their respecitive number now.

Some photoshopped versions of the pics are soon to follow in the image gallery:

http://www.pcgameshardware.de/aid,68...&show=original

I really hope I#ve not been living under a rock the last couple of months and this is really something new.

Jawed · 12-May-2009, 10:18

Awesome, great wake-up surprise.

Looks like 32 cores and 8 texture units.

Jawed

PeterT · 12-May-2009, 10:32

I don't know much about how hw structures look on a die shot but this seemed fairly obvious:

fellix · 12-May-2009, 10:51

Me helps with some photochopin' -- here and here.

entity279 · 12-May-2009, 10:59

Quote:

Originally Posted by PeterT

I don't know much about how hw structures look on a die shot but this seemed fairly obvious:

Yup.

Jawed · 12-May-2009, 11:01

What looks like the GDDR interface is interesting as there's so much of it. If the die is 30x20 (which I think is a bit small) then that means the DDR interface is about 54mm.

The 256-bit GDDR5 on RV770 is about 36mm. The 512-bit GDDR3 on GT200 is about 75mm.

Larrabee has a 384-bit bus? GDDR3?

Jawed

fellix · 12-May-2009, 11:09

Can anyone spot the PCIe interface pads somewhere?

V3 · 12-May-2009, 11:19

Is Larrabee going to be competitive with 8 texture units ?

Jawed · 12-May-2009, 11:22

Quote:

Originally Posted by fellix

Can anyone spot the PCIe interface pads somewhere?

Top-right, vertically? Based on my earlier measurements, 8.1mm. Compared to 8.8mm on RV770 and 7.7mm on G80.

Jawed

Jawed · 12-May-2009, 11:28

Quote:

Originally Posted by V3

Is Larrabee going to be competitive with 8 texture units ?

Assuming they're quads, that's 32. The clock is the real killer question.

Larrabee should have the best overdraw reduction (other GPUs' early Z rejection is coarse-grained and so conservative).

Dunno, at 1GHz it doesn't seem likely.

Jawed

PeterT · 12-May-2009, 11:43

Quote:

Originally Posted by Jawed

The 256-bit GDDR5 on RV770 is about 33mm. The 512-bit GDDR3 on G80 is about 67mm.

Larrabee has a 384-bit bus? GDDR3?

G80 had a 384 bit bus. Did you mean GT200?

Jawed · 12-May-2009, 11:46

Quote:

Originally Posted by PeterT

G80 had a 384 bit bus. Did you mean GT200?

Whoops, sorry, yeah.

Jawed

kyetech · 12-May-2009, 13:14

I bet this is a mainstream part. They are saving the high end to surprise us. nearer launch.

fellix · 12-May-2009, 13:20

Red - 32 cores
Green - 8 structures (?)
Blue - 4 structures (?)

AlStrong · 12-May-2009, 13:30

Quote:

Originally Posted by kyetech

I bet this is a mainstream part. They are saving the high end to surprise us. nearer launch.

900mm^2?

PeterT · 12-May-2009, 14:03

One more, because photoshop is fun.

If the green blocks are texture units, then what are the blue ones? They are strangely asymmetrical.

Jawed · 12-May-2009, 14:10

Blue ones for bus<->memory?

One thing I'm wondering is if Intel has built the DDR interface in two parts, GDDR3, say 256-bit and GDDR5, 128-bit. Rather than trying to make the interfacing multifunctional.

Or, maybe it's 256-bit GDDRx + 128-bit "communicate with another Larrabee"?

Jawed

fellix · 12-May-2009, 14:33

The x86 cores are very Atom-like in shape. The L2 array can definitely be spotted in the one end of the tile, and in the opposite end there is also some uniform array of structures (registers ?).

3dilettante · 12-May-2009, 14:51

The cores are more svelt than my guesstimated lower bound of ~18mm2.
It's what, 15 or so? I unfortunately don't have time to do more than glance.

At 32 cores, Larrabee would have two short-linked rings of 16.
Other statements said that the bus was routed over the L2.
The odd part is that the caches don't really point to a very even distribution.

The four blue sections would fit with the desire to space memory controller ring stops evenly, and they could also be used to serve as the connection points that connect the two rings.

Jawed · 12-May-2009, 14:56

12mm²?

fellix · 12-May-2009, 14:56

Now, I wonder what will heat up this thing more -- FurMark or some weird port of the IBT (Linpak) test?

fellix · 12-May-2009, 15:02

Silverthorne die (Atom) in a LRB disguise -- minus half the L2 and the AGTL+ interface.
Imagine the SIMD unit for yourself!

Sound_Card · 12-May-2009, 15:04

Quote:

Originally Posted by kyetech

I bet this is a mainstream part. They are saving the high end to surprise us. nearer launch.

Can anyone guess a die size on this one?

AlStrong · 12-May-2009, 15:07

Quote:

Originally Posted by Sound_Card

Can anyone guess a die size on this one?

32->48 cores?

http://forum.beyond3d.com/showpost.p...2&postcount=15

Sound_Card · 12-May-2009, 15:15

Quote:

Originally Posted by AlStrong

32->48 cores?

http://forum.beyond3d.com/showpost.p...2&postcount=15

I don't believe this is 900mm2.

12-May-2009, 09:54	#1
CarstenS Just wondering Join Date: May 2002 Location: Germany Posts: 1,377	Larrabee Die-Shot - Analyze this Today, intel showed the first detailed die-fotograph of Larrabee - some pictures are to be seen at PC Games Hardware. http://www.pcgameshardware.de/aid,68...fikkarte/News/ Some of the functional units can be distinguished also - pleases take your guesses as to their respecitive number now. Some photoshopped versions of the pics are soon to follow in the image gallery: http://www.pcgameshardware.de/aid,68...&show=original I really hope I#ve not been living under a rock the last couple of months and this is really something new. __________________ English is not my native tongue. So please, before being too nitpicky about my choice of words, please consider the possiblity that I did not mean to say what you might have read into them and inquire if not sure. Twitter Did you know? The Future is Fusion!

12-May-2009, 10:51	#4
fellix Senior Member Join Date: Dec 2004 Location: Varna, Bulgaria Posts: 1,509	Me helps with some photochopin' -- here and here. __________________ Baby, It's Cold Outside

12-May-2009, 11:01	#6
Jawed Regular Join Date: Oct 2004 Location: London Posts: 8,532	What looks like the GDDR interface is interesting as there's so much of it. If the die is 30x20 (which I think is a bit small) then that means the DDR interface is about 54mm. The 256-bit GDDR5 on RV770 is about 36mm. The 512-bit GDDR3 on GT200 is about 75mm. Larrabee has a 384-bit bus? GDDR3? Jawed Last edited by Jawed; 12-May-2009 at 19:41. Reason: G80->GT200 - GT200=75 - RV770=36

12-May-2009, 11:09	#7
fellix Senior Member Join Date: Dec 2004 Location: Varna, Bulgaria Posts: 1,509	Can anyone spot the PCIe interface pads somewhere? __________________ Baby, It's Cold Outside

12-May-2009, 13:14	#13
kyetech Member Join Date: Sep 2004 Location: Eastbourne, England, UK. Posts: 468	I bet this is a mainstream part. They are saving the high end to surprise us. nearer launch. __________________ ____________________________________ Why buy one, when you can have two at twice the price?

12-May-2009, 10:18	#2
Jawed Regular Join Date: Oct 2004 Location: London Posts: 8,532	Awesome, great wake-up surprise. Looks like 32 cores and 8 texture units. Jawed

12-May-2009, 10:32	#3
PeterT Member Join Date: May 2002 Location: Austria Posts: 688	I don't know much about how hw structures look on a die shot but this seemed fairly obvious:

12-May-2009, 11:19	#8
V3 Senior Member Join Date: Feb 2002 Posts: 2,813	Is Larrabee going to be competitive with 8 texture units ?

12-May-2009, 13:20	#14
fellix Senior Member Join Date: Dec 2004 Location: Varna, Bulgaria Posts: 1,509	Red - 32 cores Green - 8 structures (?) Blue - 4 structures (?) __________________ Baby, It's Cold Outside

12-May-2009, 14:03	#16
PeterT Member Join Date: May 2002 Location: Austria Posts: 688	One more, because photoshop is fun. If the green blocks are texture units, then what are the blue ones? They are strangely asymmetrical.

12-May-2009, 14:10	#17
Jawed Regular Join Date: Oct 2004 Location: London Posts: 8,532	Blue ones for bus<->memory? One thing I'm wondering is if Intel has built the DDR interface in two parts, GDDR3, say 256-bit and GDDR5, 128-bit. Rather than trying to make the interfacing multifunctional. Or, maybe it's 256-bit GDDRx + 128-bit "communicate with another Larrabee"? Jawed

12-May-2009, 14:33	#18
fellix Senior Member Join Date: Dec 2004 Location: Varna, Bulgaria Posts: 1,509	The x86 cores are very Atom-like in shape. The L2 array can definitely be spotted in the one end of the tile, and in the opposite end there is also some uniform array of structures (registers ?). __________________ Baby, It's Cold Outside

12-May-2009, 14:51	#19
3dilettante Senior Member Join Date: Sep 2003 Location: Well within 3d Posts: 2,535	The cores are more svelt than my guesstimated lower bound of ~18mm2. It's what, 15 or so? I unfortunately don't have time to do more than glance. At 32 cores, Larrabee would have two short-linked rings of 16. Other statements said that the bus was routed over the L2. The odd part is that the caches don't really point to a very even distribution. The four blue sections would fit with the desire to space memory controller ring stops evenly, and they could also be used to serve as the connection points that connect the two rings. __________________ Dreaming of a .065 micron etch-a-sketch.

12-May-2009, 14:56	#20
Jawed Regular Join Date: Oct 2004 Location: London Posts: 8,532	12mm²?

12-May-2009, 15:02	#22
fellix Senior Member Join Date: Dec 2004 Location: Varna, Bulgaria Posts: 1,509	Silverthorne die (Atom) in a LRB disguise -- minus half the L2 and the AGTL+ interface. Imagine the SIMD unit for yourself! __________________ Baby, It's Cold Outside

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