Xbox One (Durango) Technical hardware investigation

Discussion in 'Console Technology' started by Love_In_Rio, Jan 21, 2013.

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  1. Ketto

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    VGleaks just simply didn't fully understand the information they were given?

    Edit: Or what this fine chap below me suggests.
     
    #1101 Ketto, Feb 13, 2013
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  2. ERP

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    Probably a ROP limitation
    16ROPSx8(Color+Z)x800e6
    is basically the bandwidth to the ESRAM
    That would mean that the high 16x ZFill rate, and 16bit color is relying on compression to reach the peak, which is probably normal.
     
  3. Love_In_Rio

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    #1103 Love_In_Rio, Feb 13, 2013
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  4. Love_In_Rio

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    You guys must crunch those 32 rops like doritos ;)
     
  5. SanGreal

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    Well it comes from vgleaks (I know since I rehosted it on imgur). The original image is here: http://www.vgleaks.com/wp-content/uploads/2013/02/memory_system.jpg

    If we are going to believe the rest of their info it seems silly to throw this one at as inaccurate.

    edit: I thought the speed difference might be due to an inability to write to both pools at once (102 would then be the ceiling), but I'm sure ERP's answer makes more sense
     
    #1105 SanGreal, Feb 13, 2013
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  6. Proelite

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    What do you make of the entire setup? Is there something that they could change / add to increase performance without needing to scale up the rest of the system and run into diminishing returns?

    EDIT: I wonder were the Kinect MEC processor and SHAPE Audio block are.

    http://www.vgleaks.com/wp-content/uploads/2013/01/durango_arq1.jpg

    The old diagram was vague.

    I guess they're off the southbridge if the newer diagram is accurate?
     
    #1106 Proelite, Feb 14, 2013
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  7. patsu

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    Gah... if we are talking about GPGPU type work this gen, then it's more a comparison between the VMX and Cell. The LocalStores have small latency (6 cycles constant), which indeed contributes to the SPUs' speed. But more importantly, it's achieved via high data locality.

    As long as the developers structure their data and code properly, we should be hitting the CPU and GPU caches (or LocalStore) most of the time. GCN is more efficient than traditional VLIW units. The HSA architecture also minimizes/avoids unnecessary copying between the CPU and GPU, so most of the time should be spent on the jobs themselves.

    For more random access type jobs, it will be more problematic. Nonetheless people have done tree walk and CABAC calculations on Cell's measly 256K LocalStore + DMA.

    Durango and Orbis both have more lenient memory hierarchy. They should behave just fine, with reasonable efficiency, as long as the developers are diligent.

    [size=-2]Please pay the developers and artists... They are the ones who will make the most differences.[/size]
     
  8. scently

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    I would assume that they are drawing these diagrams themselves from the info they have. Their document on the durango gpu has it accessing both memory pool at full speed.
     
  9. Lucid_Dreamer

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    So, only once the 68GB/s DDR3 fills the ESRAM/eDRAM can a burst of 170GB/s be achieved, right? Once that burst is done, it's back to 68GB/s, until the 32MB ESRAM/eDRAM is full, right?
     
  10. ERP

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    I wouldn't assume that at all I'd say these diagrams are most likely from a developer presentation. Probably several developer presentations.
    When you draw diagrams like this you are trying to give an overview, it's not intended to be physically accurate representative of the system.
     
  11. Lucid_Dreamer

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    If it's DDR3, what other choices are there? Unless it's stacked for greater than 68GB/s, that's the main memory bandwidth (only game in town), right? ESRAM/eDRAM can't make DDR3 give data faster than it's limit, can it?
     
  12. ERP

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    Wasn't responding to your post, I was responding to the one above, I should have quoted it.
     
  13. dobwal

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    #1113 dobwal, Feb 14, 2013
    Last edited by a moderator: Feb 14, 2013
  14. dobwal

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  15. dobwal

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    Its not cheap silicon. SRAM isn't inconsequential from a cost standpoint.

    There wasnt a unified shader part in the PC space for a full year after the release of the 360. So MS doing something nVidia hasn't done is not new.

    nVidia nor AMD are really pushing for a high performance low bandwidth part especially if its built around adding more silicon in an effort to alleviate the cost of memory. There is a reason the 360 daughter die has never been replicated on PC gpus. For the most part the cost of memory is absorbed by their clients as AMD and nVidia business revolves around selling chips not cards.

    If you want a low bandwidth part from nVidia or AMD its going to come with rather subpar performance because for the most part no one expects high performance from cheap PC products. AMD apu perform pretty well from a lowend part but that seems more a consequence of AMD's desire to make their apu really relevant in the gpgpu space and that manufacturing small apus is better on their bottom line than putting out highend parts.

    I think people seem to underestimate MS's focus on their gaming division. Looking at a list of MS's patents that have gaming implication will show you how much R&D they are putting towards this area. Furthermore, their efforts are broader than either nVidia or AMD as their focus is hardware while MS basically covers a broader spectrum of gaming. Their R&D department dwarfs either nVidia and AMD combined.
     
  16. patsu

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    Supercomputing apps may be more concerned with solving large problems. They may be able to hide latency well.

    They may want higher "density" too (more performance per watt, and more precision).

    Efficiency is also important (e.g., least overhead).

    Games devs need 360 to focus on graphics work. MS only used it for Kinect computation.

    The VMXes are the main compute units.
     
  17. bkilian

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    Yes, technically it can perform computations using the GPU, thanks to it's MEMEXPORT ability. We used it extensively for decoding H.264. It's still not GPGPU as understood and used today. It was a forward looking feature in the GPU with very few useful applications. That's why I said "to speak of" as opposed to "at all"
     
  18. Scott_Arm

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  19. Silenti

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    Perhaps this is a silly question. Quick preface: Something doesn't wash here. Just a gut feeling from myself. Hard to explain. I just don't quite buy the assumptions that are being passed around to fill in the missing parts/ lack of detail in the VGleaks docs. Specifically I just don't buy that it's a fairly straightforward mod of a 7xxx.

    Assuming that the 32mb of ESRAM is correct, how would anyone here change the GPU to take better advantage of that? MS seems to have spent a fair amount on that addition and the comments here seem to state it is not enough to make up for a lack main RAM bandwidth.

    Maybe I am just in a state of shock. MS didn't miss a trick last time out. Something just doesn't feel right.
     
  20. dobwal

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    I added the link after I wrote the statement.

    My bad. My understanding of how DMAs worked was terribly off.
     
    #1120 dobwal, Feb 14, 2013
    Last edited by a moderator: Feb 14, 2013
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