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Xbox360 graphics processor update: it has 332 million transistors! [up from 150 million previously reported]

M

midnightgamer

Junior Member

it was first reported that the ATI GPU in Xbox360, was only 150 million transistors, which is less than ATI's current R420 and R480 GPUs used in the Radeon X800 series and X850 series of cards.

http://xbox360.ign.com/articles/612/612995p1.html

the Graphic Processing Unit, which handles the graphic output of the system (and which has 150 million transistors in it),
Click to expand...

that was over a week ago, from May 12th.


now today (Well Friday, May 20th that is, it is now Saturday) it is being reported that the ATI GPU in Xbox360, now known as "Xenos" has 332 Million transistors. this is split between the two dies of the GPU-package. there are 232 million transistors in the main GPU die, and another 100 million in the "daughter" die that has the 10 MB of eDRAM and additional circuitry for anti-aliasing, including 192 mini-processors that surround the eDRAM.


Lastly, we were sent updated spec numbers on the Xbox's numbers, and we spoke with Microsoft's Vice President of hardware, Todd Holmdahl, about the Xbox 360's final transistor count.

Another bit of information sent our way is the final transistor count for Xbox 360's graphics subset. The GPU totals 332 million transistors, which is spit between the two separate dies that make up the part. The parent die is the "main" piece of the GPU, handling the large bulk of the graphics rendering, and is comprised of 232 million transistors. The daughter die contains the system's 10MB of embedded DRAM and its logic chip, which is capable of some additional 3D math. The daughter die totals an even 100 million transistors, bringing the total transistor count for the GPU to 332 million.
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http://xbox360.ign.com/articles/617/617951p3.html

this brings the total amount of transistors in Xbox360's GPU to *over* the amount that is in the PS3's Nvidia RSX Reality Synthesizer GPU which has 300 million transistors, even though the RSX is still likely to contain more logic transistors than the Xbox360 GPU.
 
EDRAM will probably never see the light of day in the desktop R520 chip. 332M transistors is a hella lotta transistors to be fitting onto a die with 90nm transistors. Assuming that half the main parent die is made up of SRAM blocks, the total diesize will probably be no smaller than 160mm2, or twice the size of a Winchester/Venice.
 
i would expect the nVidia core to wiegh in around 300+ million trannies anyway, 24 pipes is going to take up a lot of die space.
 
Originally posted by: Goi
EDRAM will probably never see the light of day in the desktop R520 chip. 332M transistors is a hella lotta transistors to be fitting onto a die with 90nm transistors. Assuming that half the main parent die is made up of SRAM blocks, the total diesize will probably be no smaller than 160mm2, or twice the size of a Winchester/Venice.
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well I think that it end up not being too many transistors because its actually 2 seperate dies on one package

 
Well I'm talking about combined area here. Regardless of whether it's 2 dies or 1, it's still gonna take up around the same total area and power consumption.
 
i was a bit taken back by the 2 seperate core idea, is one bit the GPU and then the other bit the EDRAM and the memory controller?

its probably that big because it basically has to house a 10mb cache, and a memory controller logic for the xbox360. the two chips are connected by a wide 2Ghz bridge or something arent they? sounds nutty!

so the GPU takes up like 230 odd million trannies, and its been termed as a 48 way pipeline core, which im not sure if that actually means 48 pipes.

the RSX is 300Million so NV have got something pretty complicated there. and they dont have EDRAM or a memory controller to worry about
 
Now I'm wondering exactly how the XBox 360 is going to be cooled? Or is 360 referring to the operating temp? I keep reading more and more about high transistor counts.
Tas.
 
Originally posted by: otispunkmeyer
i was a bit taken back by the 2 seperate core idea, is one bit the GPU and then the other bit the EDRAM and the memory controller?

its probably that big because it basically has to house a 10mb cache, and a memory controller logic for the xbox360. the two chips are connected by a wide 2Ghz bridge or something arent they? sounds nutty!

so the GPU takes up like 230 odd million trannies, and its been termed as a 48 way pipeline core, which im not sure if that actually means 48 pipes.

the RSX is 300Million so NV have got something pretty complicated there. and they dont have EDRAM or a memory controller to worry about
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As stated in the OP, the daughter die is the EDRAM and anti-aliasing stuff.
And it's 48 ALU's, which has been said over and over, not 48 pipes.
 
to make things even more confusing, the latest information says that there are 4 ALUs in each of the 48 unified shader pipes.

before, it was 48 ALU pipes or 48 ALUs.


I will get a link to the newer information that suggests 4 ALUs per 48 pipes, later today.
 
Originally posted by: midnightgamer
to make things even more confusing, the latest information says that there are 4 ALUs in each of the 48 unified shader pipes.

before, it was 48 ALU pipes or 48 ALUs.


I will get a link to the newer information that suggests 4 ALUs per 48 pipes, later today.
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this is what confuses me also

ive heard 48way pipelines, then 48pipelines with 2-4ALUs per pipe.....
 
Originally posted by: tasburrfoot78362
Now I'm wondering exactly how the XBox 360 is going to be cooled? Or is 360 referring to the operating temp? I keep reading more and more about high transistor counts.
Tas.
Click to expand...


water cooling apparently

 
Wow, that's really impressive...not.

Why is it that the PS3 had so many real time & prerendered vidoes ready to go at E3 & Xbox had those lame G5 or whatever vids. Isn't the Xbox supposed to release before PS2? lol
 
Originally posted by: Pr0d1gy
Wow, that's really impressive...not.

Why is it that the PS3 had so many real time & prerendered vidoes ready to go at E3 & Xbox had those lame G5 or whatever vids. Isn't the Xbox supposed to release before PS2? lol
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no. ps2 was released before XBOX. But Xbox 360 is suppose to be released before PS3 😛
 
That is because the XBOX 360 was showing actual game development. They could have created and showed pre-rendered stuff like Sony. That just tells me that game development is much farther along on the XBOX 360 than the PS3.
 
Originally posted by: michaelpatrick33
That is because the XBOX 360 was showing actual game development. They could have created and showed pre-rendered stuff like Sony. That just tells me that game development is much farther along on the XBOX 360 than the PS3.
Click to expand...


given the fact that PS3 is probably more than 1 year away and XBOX360 is out at xmas....id hope the game dev is much further on
 
ok, as promised, here is one of the quotes from one of the articles about each of the 48 shader pipes having 4 ALUs

http://www.techreport.com/etc/2005q2/xbox360-gpu/index.x?pg=1

Unified shaders
Feldstein cited several major areas of innovation where the Xbox 360 GPU
breaks new ground. The first of those is the chip's unified shader array,
which does away with separate vertex and pixel shaders in favor of 48
parallel shaders capable of operating on data for both pixels and vertices.
The GPU can dynamically allocate shader resources as necessary in order to
best address a computational constraint, whether that constraint is vertex-
or pixel-related.

This sort of graphics architecture has been rumored as a future possibility
for some time, but ATI worried that using unified shaders might cause some
efficiency loss. To keep all of the shader units utilized as fully as
possible, the design team created a complex system of hardware threading
inside the chip itself. In this case, each thread is a program associated
with the shader arrays. The Xbox 360 GPU can manage and maintain state
information on 64 separate threads in hardware. There's a thread buffer
inside the chip, and the GPU can switch between threads instantaneously in
order to keep the shader arrays busy at all times.

This internal complexity allows for efficient use of the GPU's computational
resources, but it's also completely hidden from software developers, who
need only to write their shader programs without worrying about the details
of the chip's internal thread scheduling.

On chip, the shaders are organized in three SIMD engines with 16 processors
per unit, for a total of 48 shaders. Each of these shaders is comprised of
four ALUs that can execute a single operation per cycle, so that each shader
unit can execute four floating-point ops per cycle.
Click to expand...


 
Originally posted by: Goi
Well I'm talking about combined area here. Regardless of whether it's 2 dies or 1, it's still gonna take up around the same total area and power consumption.
Click to expand...
The problem isn't so much the die area, it's the heat. With the PS3/Xbox360, it's a custom design which allows components and cooling hardware to be placed wherever the engineers want, whereas PC expansion cards must all fit within the PCIe/AGP specs. This doesn't mean that the next-gen console GPUs can't be used in PC's, but there definitely exists some cutoff point where freeform console design allows the kind of cooling(and therefore the kind of tech) a standards-compliant PC can't use.
 
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