AMD: R8xx Speculation

Discussion in 'Architecture and Products' started by Shtal, Jul 19, 2008.

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How soon will Nvidia respond with GT300 to upcoming ATI-RV870 lineup GPUs

Poll closed Oct 14, 2009.
  1. Within 1 or 2 weeks

    1 vote(s)
    0.6%
  2. Within a month

    5 vote(s)
    3.2%
  3. Within couple months

    28 vote(s)
    18.1%
  4. Very late this year

    52 vote(s)
    33.5%
  5. Not until next year

    69 vote(s)
    44.5%
  1. OpenGL guy

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    No, it doesn't work that way. Early-Z means do the full RBE Z before the pixel shader. This way you reduce shader workload. Late-Z means do the full RBE Z after the shader. These are independent of HiZ and have been around since at least R300.
    The only time you'd need to disable HiZ is if the pixel shader were outputting Z.
     
  2. elsence

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    I said the opposite, i said that probably the 5870 is bandwidth limited...

    So let's take the 5870 vs GTX285 data.
    Is the 5870 less bandwidth limited than GTX285?
    I don't know.

    For example:
    Let's compare GTX285 with GTS250 (much more similar than your comparison ATI vs NV architecture...)

    GTX285 has +75% the pixel fillrate and only +10% the texel fillrate of GTS250 and +125% the memory bandwidth.

    What i can tell for sure is that NV made a terrible design with GTX285, lol

    But let's say that your assumption is correct, i don't want to argue about this at all.

    This isn't the major role imo, the major role is that the 850MHz 32ROPs/1600SP ATI design has better specs than the GTX285.

    For example:

    Take a GTS250 (738MHz core / 1100MHz mem) and underclock the mem at 900MHz.
    Take a low power 55nm 9600GT SKU (600MHz core / 900MHz mem)
    You can clearly see that the underclocked GTS250 is more bandwidth limited than the 9600GT.
    Despite that it is increasing its lead...


    Certainly ATI's antialiasing algoriths brought so far less hit than NV's, especially in the 8X case.
    That's why in my analysis of the AMD data, i suggested not to include the 8X data, because it can lead to wrong conclusions.
    I don't care if the 5870 is more bandwidth limited in relation with GTX285.
    I care if the 5870 is bandwidth limited by itself.
    In the sense: if we increase the mem speed from 1,2GHz to 1,5GHz, if we gonna see a significant perf. increase...
     
  3. elsence

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    Yep, it is natural at this early stage of GDDR5.
    This happened in the past also, for example 4870 had 4Gbps Qimonda ICs and ATI clocked them at 900MHz (instead of 1GHz)
    I was talking about what ICs is logical for ATI to buy from companies like Samsung and Hynix at this stage.

    I search the web, i found some reviews:

    http://www.bit-tech.net/hardware/graphics/2008/11/28/gigabyte-gv-r485mc-1gh-radeon-hd-4850-1gb/1

    http://www.hardwarecanucks.com/foru...gabyte-radeon-hd-4850-1gb-passive-review.html

    http://www.bjorn3d.com/read.php?cID=1527&pageID=6566

    It seems to me that +33% (4/3) is a fair average at 1920X1200 4X AA 16X AF.
     
  4. Silent_Buddha

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    Well, there is still that rumor that ATI will be launching 4 chips. So far we've only gotten confirmation (somewhat) of two of them. Rv870 and Rv840(?). So there's still possibly two more that haven't been leaked.

    Regards,
    SB
     
  5. Alexko

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    Sure they have:

    [​IMG]
     
  6. Silent_Buddha

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    Ah, right-o, so the other two will be released in Q1 2010.

    Regards,
    SB
     
  7. mczak

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    Well so redwood/cedar only launch next year. So no 4850 replacement for now neither (well maybe by that time 5750 will be used at the 100$ spot...).
    Plus I sort of doubt redwood will achieve HD 4850 performance even in a high-end configuration.
     
  8. FrameBuffer

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    iirc the 5850 is the 4850 segment replacement. Or are you referring to the current pricing ? That will for the most part rely upon the competition. 48XX series last I heard will go into EOL status after launch. Rv840 series could see dayligt earlier however there is little incentive until the channel is cleared some.
     
  9. fellix

    fellix Hey, You!
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    By the way, looking at the test drivers' CCC for 5870, I can't find any different settings regarding changes or additions to the available AA modes.
     
    #3369 fellix, Sep 18, 2009
    Last edited by a moderator: Sep 19, 2009
  10. Acert93

    Acert93 Artist formerly known as Acert93
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    I have followed this thread off and on but have not been able to keep up. Any word on multi-chip designs on a single package, Crossfire enchancements, etc? Memory footprint utilization, latency, geometry, etc are all interesting issues for SLI like approaches and I am curious to know if AMD did much to make Crossfire more efficient/better results in these areas. Getting multiple chips working as a simple chip is a big task, curious to see if any unfounded rumors had any merit. Thanks!
     
  11. 3dilettante

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    No word on any of that.
    There's no shot of what's under the cooler for the alleged X2 board, it just appears to be longer.

    The diagrams make no mention of a crossfire sideport, though there is a crossfireX compositor in a similar area of the diagram.
    The compositor still hangs off of the hub, and barring an improvement there, there would be no point for a super high-bandwidth link between the chips.
    There isn't much else given other than the box on the diagram.
     
  12. Alexko

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    Well there are rumors saying that Redwood has 640 SPs, but I doubt that: it's too close to Juniper (800). My bet's on 480 SPs in which case, indeed, Redwood can't achieve 4850-level performance.

    But yeah, from what we're hearing, Juniper-based cards sure seem a little too expensive. They have low power consumption, Eyefinity and DX11 on their side, but I don't think that will be enough to woo people away from the cheaper 4800s.
     
  13. LordEC911

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    Have we gotten any confirmation on that SP count?
    I'm still leaning towards 960SPs, which was part of the reason why some thought RV790 was going to have the same setup, plus it will decrease the gap between Juniper XT and Cypress Pro.
     
  14. Silent_Buddha

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    Hmm, that new cooler actually doesn't look half bad once you get the AIB logo's and graphics on them...

    http://gathering.tweakers.net/forum/view_message/32598832

    They need to switch the girls though, the one on the 5850 is much tougher looking than the 5870 girl. ;) Dual Swords FTW!@#!@#

    And pretty amazed at how cool it stays even at load at 30% fanspeed with that tiny exhaust opening.

    Regards,
    SB
     
  15. trinibwoy

    trinibwoy Meh
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    Yeah you're right, that's a big improvement. They could still do with some help from Apple's design team though.
     
  16. Chris123234

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    I spazzed out for a second at this typo:

    ______________________________________________

    The 5870 Six is the most beautiful(ly clean faceplate) card I've ever seen. What is the premium on this one? And does the X2 come with a Six (or Twelve) version?
     
    #3376 Chris123234, Sep 19, 2009
    Last edited by a moderator: Sep 19, 2009
  17. turtle

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    Really curious about this myself as of late.

    960 really does seem to make sense, business-wise, even if it is against the conventional [strike]wisdom[/strike] rumors.

    I could write my typical page of bullshit why either would make sense (regarding timing of release, die size, price, competition, etc) but I'll refrain...just this once.

    :lol:
     
  18. 3dcgi

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    You only need to setup the verts to get their screen space position. You don't need to finish rasterization by determining pixel coverage.
     
  19. 3dilettante

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    My interpretation of Larrabee's software rasterizer is that it does get coverage during bin setup.
    The bins will contain coordinates and coverage info for the triangles.
    Perhaps I'm not interpreting this correctly:

     
  20. 3dcgi

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    The quote does seem to indicate that though it seems wasteful for large triangles. I'd think you want to bin before amplification (scan conversion).
     
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