Xbox One (Durango) Technical hardware investigation

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I think everyone is running around in circles. Lets just define some stuff so it doesn't get out of hand.

At some point last year, Microsoft had an idea of X CPU and Y GPU they were going to use at C1 and G1 clock speed respectively. At some point before the end of last year, that silicon really needed to be finalized in order for testing to be completed and production ramp up to be good enough for yields to launch this year. This event would have had to have happened before the Playstation Meeting. Whatever actual silicon they produced, X and Y chip designs cannot have changed before the end of 2012. Period.

You have facts to back this up?

It was less than 6 months before launch of the 360 that they had final silicon. So a compressed time line isn't out of the realm of possibility. I doubt they want to repeat it, but I don't think they need a year either.
 
Durango (XB720) technical hardware investigation (news and rumours)

You have facts to back this up?

It was less than 6 months before launch of the 360 that they had final silicon. So a compressed time line isn't out of the realm of possibility. I doubt they want to repeat it, but I don't think they need a year either.

I used the wrong word. I shouldn't have said finalized. I should have said "taped out" for an initial production run: http://semiaccurate.com/2012/01/18/xbox-nextxbox-720-chips-in-production/#.UUvZN_q9LCQ

SemiAccurate seems "knowledgeable enough".
 
http://www.anandtech.com/show/6837/...w-feat-sapphire-the-first-desktop-sea-islands

Our first full review?

So what are we looking at for Bonaire and the 7790? As the 7790 will be a fully enabled Bonaire part, what we’ll be seeing with the 7790 today will be everything that Bonaire can offer. On the specification front we’re looking at 14 CUs, which breaks down to 896 stream processors paired with 56 texture units, giving Bonaire 40% more shading and texturing performance than Cape Verde. As a further change to the frontend, the number of geometry engines and command processors (ACEs) has been doubled compared to Cape Verde from 1 to 2 each, giving Bonaire the ability to process up to 2 primitives per clock instead of 1, bringing it up to parity with Pitcairn and Tahiti. Finally, the backend remains unchanged; like Cape Verde, Bonaire has 16 ROPs attached to a 128bit memory bus, giving it equal memory bandwidth and equal ROP throughput at equivalent clockspeeds.

Moving on to the 7790 in particular, the 7790 will be shipping at a familiar 1GHz, the same core clockspeed as the 7770. So all of those performance improvements due to increases in functional units translate straight through – compared to the 7770, the 7790 has 40% more theoretical compute/shading performance, 40% more texturing performance, 100% more geometry throughput, and no change in ROP throughput. Meanwhile in a move mirroring what AMD did with the 7970 GHz Edition last year, AMD has bumped up their memory clocks. 7790 will ship with a 6GHz memory clock thanks to a higher performing (i.e. not from Cape Verde) memory interface, which compared to the 7770’s very conservative 4.5GHz memory clock means that the 7790 will have 33% more memory bandwidth compared to 7770, despite the fact that the memory bus itself is no wider.

Putting it altogether, so as long as the 7790 is not ROP bottlenecked, it stands to be 33%-100% faster than the 7770. Or relative to 7850, the 7790 offers virtually all of the 7850’s texturing and shading performance (it’s actually 2% faster), while offering only around 60% of the memory bandwidth and ROP throughput.

As for AMD’s functional unit layout for Bonaire – 14 CUs, 2 geometry pipelines, and 16 ROPs – it looks to have paid off handsomely for them. They’ve improved performance by quite a bit without having to add too many transistors or a larger memory bus, making it a great way to iterate on GCN midway between new process nodes.
 
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Oh, no, I don't mean to imply that this is what the Durango GPU will be, but merely that it's likely the closest thing in existence to what the Durango GPU is, and as such is probably not a bad place to look when trying to get a decent idea for performance.

Before, the 7770GHZ was the best thing we could compare it to, but now this GPU is, as Durango has more in common with the 7790. And while Durango's GPU has less CUs and is clocked at 800MHZ, it also has access to quite a bit more memory bandwidth, low latency ESRAM that Microsoft says will benefit ROP performance, and then there's the Move Engines. Not pretending that these are magical additions, but they obviously wouldn't be there if they didn't help in some important fashion. Toss in console related benefits and I think you've got a pretty capable performer at a fairly nice level of power consumption.

I think the chances of it being Bonaire are just as strong as the chance that it isn't, because it isn't as if Bonaire wasn't in planning for some time. Durango's GPU could have been finalized late last year, and there would still be a chance that it could be Bonaire, because surely Bonaire was more or less being finalized around that time also.
 
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Of course it's possible, lots of things are possible - the question is not whether it's possible or not, but whether it's likely or not, given what we know.

MS apparently knew that the PS4 was in all likelihood going to be more powerful than their box (since they'd have a high % of their BOM going to Kinect) and would have developed their strategy accordingly.

So they're definitely not going to be running around flailing their hands because the PS4 will have games that run at 30% higher resolution or something.

I don't think BOM compared to PS4 was anything Microsoft were concerned with, as by everything that has been revealed about PS4 thus far indicates it is going to have a significantly higher BOM than Durango.

I think Microsoft started with a price point they wanted to hit. Then they had a feature list that they wanted to have. And finally a performance target. Throw all that together and we end up with Durango.

It could be that they didn't expect Sony to potentially go for another loss leading console design. Or they really don't care if Sony one ups them in performance. Looking at the state of PC games, while the performance delta with same features enabled between a 7770 and 7850 is fairly significant, you only have to look in our very own PC gaming forum to see users there that turn down graphical settings without themselves being able to perceive any noticeable visual differences without a side by side comparison.

I do expect things to shake out differently with next gen consoles however. Since most of the games that the 7770 and 7850 had to contend with were ports from consoles with very limited memory, assets generally weren't going to push things much.

Art and art assets may play a much more significant role for Durango and Orbis and hence, why I expect slightly lower resolution for Durango games, but that when viewed on a TV at most people's viewing distances, people won't be able to tell the difference without seeing them side by side. Especially when you factor in the likelihood that the game UI and especially text will likely always be 1080p.

And, of course, this is all assuming that the performance level of Durango's GPU is roughly that of a 7770 or slightly higher and nothing that MS have done on the hardware side has made it more performant than what one would expect from the rumored information available.

TL: DR - PS4 being more powerful than Durango has nothing to do with the BOM comparison between the two. In other words, Microsoft didn't really care what the BOM of PS4 was going to be as they were following their own business plan. Hence comparing the lower total BOM of Durango to the higher total BOM of Orbis doesn't factor in to the design decisions that MS undertook.

It does allow them the luxury of either pricing lower or having higher margins and profit levels, however.

From the tech side, I'm still interested to see how things turn out. I'm hoping, but not holding my breath, that after each console is finally released to consumers we'll get a more in depth look and explanation of each consoles hardware. I would find that very interesting.

Regards,
SB
 
Whether or not the Bonaire is what Durango GPU is based on, we have to consider also that MS has traditionally always used derivates of GPUs on their consoles.

Xbox had the NV2a, which was a modified NV20.
360 had Xenos, which was based on the R500/600 but modified as well.

So we cannot really say that Durango GPU is or is not Bonaire architecture but modified.
Also, many people do say that "yeah but the leaks already states the GPU specs" but the leaks/documents also says "subject data can be changed".

It will be interesting to see what is the final silicon in Durango.. :)
 
I don't see much point to overclocking, since short of a completely new chip it's still going to be weaker than the PS4. Overclocking will just make the yields worse and their chips more expensive.

But there's degrees with most everything. You're likely better off 15% less powerful than 30% less. That can shift more of the focus to "everything else".
 
Whether or not the Bonaire is what Durango GPU is based on, we have to consider also that MS has traditionally always used derivates of GPUs on their consoles.

Xbox had the NV2a, which was a modified NV20.
360 had Xenos, which was based on the R500/600 but modified as well.

So we cannot really say that Durango GPU is or is not Bonaire architecture but modified.
Also, many people do say that "yeah but the leaks already states the GPU specs" but the leaks/documents also says "subject data can be changed".

It will be interesting to see what is the final silicon in Durango.. :)

Everything so far, and that includes the details of the 2012 February conference leaks has said that the GPU is stocked standard GCN, there probably wasn't much point going with a derivative this time, GCN is pretty damn powerful and efficient.
 
Everything so far, and that includes the details of the 2012 February conference leaks has said that the GPU is stocked standard GCN, there probably wasn't much point going with a derivative this time, GCN is pretty damn powerful and efficient.

Can you quote me where it said that? I've seen lots of allusions to GCN based, but not one that specified the limitations of GCN compared with GCN 1.1 (Bonaire which AMD really just calls GCN as well) which is apparently just a bit of enhanced compute/HSA.

MS is going to use Jaguar but limit themselves to GPU architecture released last year? If there's performance advantages to what's offered in Bonaire I wouldn't doubt they looked at it (and every other product AMD has in the pipeline).
 
Can you quote me where it said that? I've seen lots of allusions to GCN based, but not one that specified the limitations of GCN compared with GCN 1.1 (Bonaire which AMD really just calls GCN as well) which is apparently just a bit of enhanced compute/HSA.

MS is going to use Jaguar but limit themselves to GPU architecture released last year? If there's performance advantages to what's offered in Bonaire I wouldn't doubt they looked at it (and every other product AMD has in the pipeline).

IIRC doesn't GCN1.1 have multiple (like 8 or something) ACE's?. We have only seen two so far in the leaks, also the leaks have so far only shown stuff that is included in normal GCN so i see no reason not to believe it.

If there where any major changes they would be in the leaks / documents.
 
IIRC doesn't GCN1.1 have multiple (like 8 or something) ACE's?. We have only seen two so far in the leaks, also the leaks have so far only shown stuff that is included in normal GCN so i see no reason not to believe it.

If there where any major changes they would be in the leaks / documents.

Bonaire has 2 ACEs, read the Anandtech review. The way I see it, the durango gpu setup has a lot more in common to the Bonaire and Tahiti or Picairin than it does to Cape Verde. Durango gpu has 2 geometry engine, same as Picairin and Bonaire while Cape Verde has just one. The ACEs are attached to different Rasterizers and Geometry engines, same as Picairin and Bonaire, while Cape Verde has is attched to one. Also Durango has 12 CUs while Cape Verde has 10. Durango has a unified virtual address space for its gpu and cpu, same as a feature advertised for Bonaire. About the only similarity between the durango gpu and Cape Verde is the FLOPS, with Cape Verde at 1.28 and Durango at 1.23. Even the bandwidth situation is different; Durango has access to 102gb/s and 68gb/s bandwidth, Bonaire has 102gb/s bandwidth while Cape Verde has access to only 72gb/s bandwidth.

On top of all this the durango is customized with eSRAM, DMEs etc. So its more its own thing really.
 
360 had Xenos, which was based on the R500/600 but modified as well.
Xenos was based on the ill-fated R400 project, not R600 and R500 never existed either (though sometimes C1/Xenos was called that outside MS)
It's shadercore for example is most closely related to R5xx vertex shaders, nothing like VLIW in R600, memory subsystems were completely different from R600 too.
 
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