The most Detailed Tech Information on the Xbox360 yet

[Geeforcer]

When has anyone added the embedded video memory bandwidth to get the "total system bandwidth"?

Did Sony add GS bandwidth to RDRAM bandwidth and pass it off as "Total Bandwidth" for PS2?
Has Nintendo at any point added 1T-SRAM bandwidth to system bandwidth and proclaimed it "Total Bandwidth" for GC?

AFAIK, this sort of creative accounting would be a first. BTW, should be start looking at GPU internal caches now too? I mean, why not, if neither the size nor the function of memory matters anymore. That way, RSX might add terabytes per second to "total system bandwidth" of PS3.

 

[AlNom]

Bah... who cares?? We all know it's silly, so why don't we focus on this for a little while.

But of interest:

With the number of transistors being slightly larger on the Xbox 360 GPU (330M) it’s not surprising that the total programmable GFLOPs number is very close.

I assume that is with eDRAM. Pretty impressive number... and therefore $$$.

 

[Mordecaii]

I have to wonder though... if you take out the number of transistors for the memory controller and the eDRAM, how many transistors does that leave? It hardly seems fair to count those two things when comparing against the RSX.

 

[wireframe]

Anyone else notice that in this otherwise greatly exaggerated document (referring to the memory bandwidth comparison), the number of shading ops is now back to 48 billion per second...

Well, in the lower chart he has it at 80 billion, but in the later summary (4 of 4) it is 48 billion. Looks like this number has a tendency to go up when PS3 data is placed next to it.

 

[therealskywolf]

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 232 million.

From Ign.

 

[Inane_Dork]

Sony already got to respond to MS's numbers. Why no outcry there? It was called the PS3 announcement. Did y'all think Sony did not carefully choose specs based on the X360 spec sheet and then hide their fuzzy math?

Don't get me wrong, I hate all this stuff. Just be fair.

 

[Mordecaii]

I would still like to know exactly how many of those transistors are actually doing graphics calculations, and how many are for the memory controller and eDRAM...

 

[Geeforcer]

At the very least, 10*1024^2*8 =83,886,080 for RAM alone, which would leave ~16 million for controller and 192 math units.

 

[Mordecaii]

I was under the impression that the memory controller was on the actual R500 chip, not on the eDRAM daughter chip? Or am I completely off base?

 

[Geeforcer]

I was under the impression that the memory controller was on the actual R500 chip, not on the eDRAM daughter chip? Or am I completely off base?

Wait, you are right. It should be on the main chip (the shader core). This is on me.

 

[Mordecaii]

Ok, so we've established that at least 83M transistors are for the eDRAM... I wonder how much of the 232M transistors on the parent chip are for the controller? Anyone have any clue or is it not really feasible to have a relatively accurate guess on this?

 

[phat]

IMO, the additional computing capacity in this eDRAM chip has been grossly overestimated. Most of it is can probably be thought of as RAMDAC preprocessing (image resampling and baking). It surely also does Z-tests. Maybe deferred texture lookups (which would be a big plus). But certainly no lighting or vertex transformation calculations or anything akin to a shader op. Think of it as an intelligent frame buffer, which is quite innovative in itself.

 

[arhra]

I have to wonder though... if you take out the number of transistors for the memory controller and the eDRAM, how many transistors does that leave? It hardly seems fair to count those two things when comparing against the RSX.

WRT the memory controller, why not? The RSX has it's own GDDR3 memory controller, and a FlexIO interface to CELL...

 

[Megadrive1988]

omg Major Nelson = Deadmeat

 

[jvd]

omg Major Nelson = Deadmeat

where did u get that info

 

[phat]

I have to wonder though... if you take out the number of transistors for the memory controller and the eDRAM, how many transistors does that leave? It hardly seems fair to count those two things when comparing against the RSX.

WRT the memory controller, why not? The RSX has it's own GDDR3 memory controller, and a FlexIO interface to CELL...

If you want to talk about interconnect logic in transister counts...

RSX
- interconnect logic (FlexIO) to the Cell
- interconnect logic to GDDR3

X360 GPU subsystem
- interconnect logic to the eDRAM on the GPU
- interconnect logic to the GPU on the eDRAM chip
- interonnnect logic to the GDDR3 on the GPU
- interconnect logic to the CPU on the GPU

I'm counting the interconnect logic on the eDRAM chip since it's included in the total transistor count of the X360 GPU subsystem.

 

[Mordecaii]

I would assume the system's memory controller (aka the northbridge) would be rather larger than the interface connectors on the RSX, but then again there's a high chance that I'm wrong... :?

 

[jvd]

where is all the stuff like wifi going to be ? does the ps3 have a southbridge that will have hte logic for that and for the multitude of connectors it will have ?

 

[phat]

where is all the stuff like wifi going to be ? does the ps3 have a southbridge that will have hte logic for that and for the multitude of connectors it will have ?

Yes. And if I recall correctly, the SB bandwidth is 2.5GB/s. Let's add that to the total too!

 

[MechanizedDeath]

I would assume the system's memory controller (aka the northbridge) would be rather larger than the interface connectors on the RSX, but then again there's a high chance that I'm wrong... :?

How much larger is the question. Until we see a die shot, I don't know if it's practical to discuss really. RSX should have a lot more trannies going to shader core regardless. How much logic does a memory controller usually take up on one of these chips? PEACE.