xbox360 gpu explained...or so

Discussion in 'Architecture and Products' started by tEd, May 19, 2005.

  1. tEd

    tEd Casual Member
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  2. Jawed

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    Fingers-crossed that Dave will provide some insight in the next few hours!

    Jawed
     
  3. gordon

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    So it can do 4xAA at 720p with virtually no performance hit at all?
     
  4. Demirug

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    No, because AA always need some additional fillrate and shaderpower. It depends on the number of pixel with edges.

    But smart Memory will save the additional bandwith that you need for AA. Alpha blending is some other thing that need less bandwith if you have smart memory.
     
  5. rwolf

    rwolf Rock Star
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  6. hkultala

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    he said "with virtually no performance hit"

    I'd say it's splitting hairs to start complaining about extra rendering of those (about 1%?) pixels that are edge pixels, when the question was not "absolutely not any more" but "virtually not any more"
     
  7. Jawed

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    :!: :!: :!:

    It looks like an ALU is 4D. So a vertex shader can't co-issue a 4D and a scalar operation.

    I suppose if vertex shading is always going to be a relatively light load this will work out OK.

    192 ops per cycle :D in NVidia terminology. :lol:

    Jawed
     
  8. AlBran

    AlBran Ferro-Fibrous
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    a.k.a. Ati is teh win :?:

    :p
     
  9. tEd

    tEd Casual Member
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    Sounds thay can have flexible co-issue of ops or do i read it wrong? That's where the 96billion shader ops/cycle may come from
     
  10. CJ

    CJ
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    1% - 4% performance hit with 4xAA according to ATi in the Firingsquad article:

    http://www.firingsquad.com/features/xbox_360_interview/page4.asp
     
  11. Jawed

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    So not in agreement with Dave's suggestion of a 256GB/s connection between parent and daughter.

    Additionally, is this full-duplex 236Gb/s?

    I wonder if that's a typo for 256Gb? The latter is 32GB/s, of course, which is in agreement with the leak.

    Jawed
     
  12. Jawed

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    This Firing Squad interview is GREAT!!!

    Class! :twisted:

    Jawed
     
  13. Geo

    Geo Mostly Harmless
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    I wonder how those two dies get married up? Could a die come from, say TSMC, and then get married to a NEC die at NEC, for instance? What are the nitty-gritty techie details of how the interface between the two dies works? I'm not always interested in that kind of detail, but this one does interest me.
     
  14. Geo

    Geo Mostly Harmless
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    Somewhere inside ATI, somebody just winced. :wink:
     
  15. Geo

    Geo Mostly Harmless
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    :!: :?: Not even "co-owns"? ATI is licensing it back or something? Otherwise forget seeing any of this in R600. Inartful phrasing, one hopes?
     
  16. Kaizer

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    As far as I've gathered, Microsoft owns the chip design this time 'round, so they can choose where to manufacture chips and control costs. Last time, they only ordered the actual chips, and we all remember how that turned out..

    Dunno what that means for ATi's rights to develop the architecture further, though.

    Kind regards
    Kjetil
     
  17. Dave Baumann

    Dave Baumann Gamerscore Wh...
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    ALU's are 5D - Vec4+Scalar
     
  18. tEd

    tEd Casual Member
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    how you explain this sentence then?

    If it were 5D that would give you 5 floating point operation per cycle per shader right?

    It's all very confusing :?
     
  19. Dave Baumann

    Dave Baumann Gamerscore Wh...
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    I would say that its incorrect (bear in mind all this is coming out in little dribs and drabs at a very busy show).
     
  20. tEd

    tEd Casual Member
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    yes i agree there is alot of conflicting information but thanks for the clearing it up peace by peace :)
     
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