Xbox One (Durango) Technical hardware investigation

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

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  1. deanos

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    I thought you can't add bandwidth like that.
     
  2. Cjail

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    VGleaks has also published this.
     
  3. warb

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    Why not? The ESRAM will certainly be put to use.
     
  4. scently

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  5. Hardknock

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    Interesting:

     
  6. Shifty Geezer

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    Bandwidth is complicated. It depends what you are trying to measure. According to the diagram, the maximum amount of BW available to GPU is 170 GB/s. In terms of peak usable BW, there are obviously factors at play, like components consuming some of that peak BW. But that's true for every box, and why we compare peak metrics in like-for-like comparisons.
     
  7. Shifty Geezer

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    Where are they getting their estimates from? These sorts of breakdowns, although good for educating readers about how BW consumption is spread throughout the system, kinda gloss over the complete flexibility the developers have. If some developers chooses to consumer all available CPU BW, they can, leaving less for the GPU, and they can have the CPU doing barely anything freeing up more for the GPU. That's why we list peak BW speeds, so devs know what resources they have ready to choose how to use them.
     
  8. AzBat

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    The inclusion of HDMI in could just be for the ability to do overlay the OS, game or app content on another source like your Cable or Satellite TV. Why does it have to be about recording? I just think it's a bit of reach. Microsoft is about IPTV now. Recording content from other devices just doesn't seem to fit their focus.

    Tommy McClain
     
  9. scently

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    Hmmm....what does the vertex indices and commands mean? The article states: "Read bandwidth of the command buffer and index buffer is 4 GB/s." I guess what I am asking is the command and index buffer located in the DMEs? are they not supposed to be in the gpu itself?
     
  10. Love_In_Rio

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    I supposse those are the command queues from CPU to GPU via ACEs. So, data from CPU kernels to be computed in the GPU. The same as in PS4, but we do not know the number of ACEs. Standard in Southern islands is two.
     
  11. scently

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    But why is it being read from the DMEs section? Shouldn't it be in the gpu itself?
     
  12. Love_In_Rio

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    I think is a way to indicate it doesn´t travel through the ESRAM bandwidth, and that has its own path. Talking about this, where is the HSA memory management unit?. Is it the GPU memory system?. Or the move engines act like it?.
     
    #2012 Love_In_Rio, Mar 13, 2013
    Last edited by a moderator: Mar 13, 2013
  13. Betanumerical

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    Interestingly enough the max read bandwidth is 170GB/s, the max write bandwidth for the GPU is 102GB/s.
     
  14. DrJay24

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    Specific numbers aside, it is obvious they CPU and other non-GPU subsystems are sharing the DDR bandwidth with the GPU and that the 32MB eSRAM is left dedicated to the GPU. Does this not point the architecture of the system around the eSRAM to being used like the eDRAM in the PS2/360? What was the point in all the low latency talk if the CPU cannot see or use the eSRAM?
     
  15. Love_In_Rio

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    Enough for 16 rops and for a 68GB/s frame buffer.
     
  16. Rangers

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    Low latency could help the GPU too. Look up ERP's posts on the subject.
     
  17. Love_In_Rio

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    For computing absolutely. But you could have got the same with a GPU L2 size increment.
     
  18. DrJay24

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    Low latency never hurts. My point is the eSRAM integration looks designed around bandwidth. GPUs have L2 for latency issues.
     
  19. Rangers

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    wouldn't that pretty much require the framebuffer reside there then?

    and i think erp's posts suggested the documentation suggests the frame buffer to reside in the ddr, thus treating the esram as a gpu cache. a totally different paradigm than the 360 edram.

    but i could be totally off base.
     
  20. Love_In_Rio

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    The framebuffer in Durango is recommended by MS to lie on DDR3. ESRAM and L2 act like GPU scratchpads, to keep on saving the computed results to be computed again when necessary.
     
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