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Official AMD Radeon 6000 Series Discussion Thread

Discussion in 'AMD / ATI' started by TechPowerUp Forums, Jul 28, 2010.

  1. cadaveca

    cadaveca My name is Dave

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    Exactly. Crossfire on a single chip, however, there is only a single memory buffer(screw that, there is essentially 4 memory buffers, @ 64-bits and 512MB each).
     
  2. wahdangun

    wahdangun New Member

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    what do you mean "Crossfire on a single chip," ? care to explain?
     
  3. cadaveca

    cadaveca My name is Dave

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    The input, dispatch, and shader sections are basically twice what they are in Cypress. the output and memory sections are "single units". Hence the extra tesselation, etc.

    There is no real Corssfire tech, other than that the two engines split the work they are doing into tiled units, or other methods that are currently used in Crossfire.

    Essentially, gpu "pipelines" have become too "deep" when run as a single working unit, so they have "shortened" the pipeline, while icnreasing the work it does a bit, and then added another pipeline.

    In the past where we've discussed efficiency, this is how they are dealing with that. It will be alot easier to fill the gpu's shaders in this way.
     
  4. wahdangun

    wahdangun New Member

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    so in other word its like 3Dfx SLi technology where each GPU render different line ? but instread its tile in cayman?
     
  5. cadaveca

    cadaveca My name is Dave

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    Yes, in a very board sense of the terms, exactly.
     
  6. pantherx12

    pantherx12 New Member

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    That' means WOO for us right?

    I know it's on one chip so doesn't really count as such, but you should see %100 scaling vs a card with half right?

    t'awesome!

    Potentially, I won't hold my breath :laugh:
     
  7. wahdangun

    wahdangun New Member

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    but if they use that technique then i think it will have depend on great driver and make the minimum framerate lower and if the load balancing is fail we will see some glitch like tearing effect (because the"other core" can't render the tile fast enough)
     
  8. lane New Member

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    What are you talking about ? ... nothing to do with crossfire or anything like this .. it's a single chips, my shot is how is made the processors in the cards, and for the dual GPE, it's just the front end with raster, Z buffer, Tesselator, data transfer patch who is doubled, like this they can get the data send in parrallel ... AMD/ATI have allways separate the group of SIMD in 2 parts, with their own cache and data buffer structure, this allow each SIMD can access the memory separately ...

    On the cayman each SIMD group have access to his own ultra threaded dispatch, who have each 1 GPE, before it was shared ...+ all of the constant and Instruction cache are doubled now.... ( just for the exammple )

    Cayman
    [​IMG]

    Cypress
    [​IMG]

    Nvidia GF 100 and 110 ...( Nvidia seperate his simd engine in 4 GPC )
    [​IMG]
     
    Last edited: Nov 28, 2010
  9. cadaveca

    cadaveca My name is Dave

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    Please see page 68 of the slide package. :shadedshu


    You'll know the right page, as it says:


    "Dual Graphics Engines"

    "Tile-based load balancing".

    Sheesh. As if I could come up with this stuff on my own. :rolleyes:

    Maybe you should read the words next time, and not just look at the pretty pcitures.
     
    Last edited: Nov 28, 2010
  10. lane New Member

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    In the slides of AMD, what they call dual graphic engine and Tile balanced loading ..

    The graphic engine is not the GPU, it's the GPE, it's only the part dedicated to Raster and geometry processing ... In Cayman, this part will work like a dual engine in parrallel... this will allow the Cayman to be 3-4x faster in geometry vs Cypress. ( 2-3x for tesselation only ) for the rest, the cache and data transfer are doubled too on this part and no more shared...

    When you look at Cypress, you have 2 group of SMID ( of processors ), called GPC with 1 GPE in front of it who is shared by both ( so when one GPC need execute a data he need to be queued in the buffer ( cache data transfer ), in Cayman you still have this 2 GPC, but this time with 2 GPE ( no more data buffered in the cache data ), this need to buffer the data was the bigger problem of Cypress... as you can understand, this was completely slow the process... now the data will be treat simultaneously for each SIMD ( for the geometry, as Tesselation ) ....

    Now there's no need to a driver command ... as each GPE are dedicated to 1 GPC.. ( group of SIMD ) Each GPE will work with 1 GPC only... this provide a better Tile Balance loading ( no more queue in the buffer )
     
  11. cadaveca

    cadaveca My name is Dave

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    So? what's your point? I'm not trying to be rude here, I just don't understand why you posted that, after asking me what i was on about.


    MY point was that the difference in architecture make Cayman "like" crossfire on a single chip. It very closely resembles a dual-core 939 cpu, with intergrated memory controller, in it's function. This is not specific...it is not a cpu, it's a gpu.

    I am not talking in terms of specifics, but as a generalization, to make it easier to understand.

    You are using a whole low of acronyms, that will do nothing but confuse people. You've just repeated what I said earlier, but in far more technical terms...even the broad terms I used were confusing, as you can see by the posts that followed my own.
     
  12. lane New Member

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    No problem, this was the crossfire " thing " who was confuse me ( and the thing with driver and 3DFX SLI someone posted ) .... But you are right ...
    you can compare it to a dual core CPU, with a major difference, there's no need to a software or driver for choose what core/thread use, it work 100% multithreaded all the time.
     
    Last edited: Nov 28, 2010
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  13. mastrdrver

    mastrdrver

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    So I actually decided to read some of those slides this time instead of just looking at the pictures here (Expreview). Is it me or does Cayman sound a lot like a AMD cpu with maybe some Bulldozer references thrown in?

    Things like:
    Asynchronous memory dispatch (like unganged?)
    Dynamic clock control of "blocks" (similar to how cpu cores clock independently?)
    Integrated power control processor (almost exact same name Intel uses to control Turbo)
    Does the VLIW4 have two 64 bit Integers and two 32 bit Floating Point units?
    Is is able to work on both at the same time (i.e. do both FP and Int calcs on same clock, ala Bulldozer)?

    If this is all true then Cayman looks more Bulldozer ready then Bulldozer (aka production ready). I can also see Cayman beating GTX 580 too, easily.

    Also what's the significance of being able to fetch directly from the LDS? Are they possibly talking about the memory controller fetching directly from the LDS on the SMIDs? Also the slide (GPU compute) shows 8 "lines" connecting the first three steps before the shaders where as with Cypress it was only 1. Is there significance there or is it just more detail that was already there (like Barts showing the dual engines Cypress had even though the Cypress pics never showed it)?

    I can't wait till 28nm! Sounds like it could be truly epic.

    Even though the Cypress picture makes it look like it only has 1 dispatch processor it is actually like Barts in that there are two dispatch processors. Some of the Barts reviews covered this (I think maybe Tech Report & PCPer).
     
    Last edited: Nov 28, 2010
  14. cadaveca

    cadaveca My name is Dave

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    So, yeah, I think those "slides" are faked pics.

    Just like always.

    But it's interesting, anyway.
     
  15. lane New Member

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    Yes you are right, i was forget Bart ...
     
  16. wahdangun

    wahdangun New Member

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    so you are saying that in cayman they can render two separate process ? with its dual graphic engine ?
     
  17. Nokiacrazi New Member

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  18. bear jesus

    bear jesus New Member

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    Crossfire would work with that board, it says 600w recommended for crossfire on my 6870's boxes.
     
  19. Nokiacrazi New Member

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    Can you do me a huge favour and check the systems builders forum and check my thread. I can't get the link since I'm on my phone. There's a question or two you may be able to answer.
     
  20. the54thvoid

    the54thvoid

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    This will sound massively rude (and no offence meant) but you shouldn't touch system building if you dont know whether or not your mobo supports crossfire.
     
  21. bear jesus

    bear jesus New Member

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    I'm taking a look right now and the first thing i noticed is i may have something you might want, a 6870 for sale cheaper than you can buy online :D still reading the thread though.

    Come on it's not like we were all born with the knowledge we have of computers, you have to start somewhere.
     
  22. Nokiacrazi New Member

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    I knew it was crossfire compatible I was wondering about the slots whether 1 rated at 4x would be a bottleneck. But I looked elsewhere and found the answer. So really I asked a pointless qustion. :banghead:
     
  23. pantherx12

    pantherx12 New Member

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    You won't get much of a bottle neck TBH, you might take a 5% hit if you were using a two 5870s for example.
     
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  24. Nokiacrazi New Member

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    So its negligible. Much appreciated. :toast:
     
  25. bear jesus

    bear jesus New Member

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    :laugh: it thought it was x8 i guess i was not paying enough attention, but something people often forget is pci-e 2 at x4 is the same as pci-e 1 at x8.
     

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