The New and Improved "G80 Rumours Thread" *DailyTech specs at #802*

Discussion in 'Pre-release GPU Speculation' started by Geo, Sep 11, 2006.

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  1. Geo

    Geo Mostly Harmless
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    The original thread here having become unwieldy. . . .

    The B3D Forum Conventional Wisdom Watch (Minority Reports noted):

    D3D10, 500M+ transistors, release sometime between September and end of the CY, probably 80nm (tho I've seen a minority report for 90nm), possibly GDDR3 with > 256-bit bus rather than GDDR4, HDR+AA. More new goodness on the AA side too, details unclear. Non-unified ps/vs. Power-hungry beastie, almost certainly with improved cooling vs G71.

    Taking requests to add to this list. Do we have a unit count we are willing to point at as the Conventional Wisdom at this point? Xbit reported 48ps. . .willing to go with that for the moment?

    Depending on how lazy I and my brethren are, we might try to keep this OP updated with particularly interesting new tidbits as they come in downstream, as an experiment to see how it works. Should be noted with "Update:"

    Please note that this post is just meant to reflect the speculation included herein (and the previous thread, of course), rather than an official position of B3D, Inc! :lol:

    Some relevant linkage along the way from the previous thread, for which only the authors are responsible for the accuracy thereof (i.e. don't bitch to me!):

    http://www.xbitlabs.com/news/video/display/20060220100915.html
    http://www.cooltechzone.com/Special_Reports/Insider_Series/NVIDIA_G80_Delayed_200604092276/
    http://www.beyond3d.com/forum/showthread.php?t=30014
    http://www.dailytech.com/article.aspx?newsid=2785
    http://www.theinquirer.net/default.aspx?article=32385
    http://www.beyond3d.com/forum/showthread.php?p=775737#post775737
    http://www.theinquirer.net/default.aspx?article=32768
    http://www.theinquirer.net/default.aspx?article=32856
    http://www.digitimes.com/NewsShow/MailHome.asp?datePublish=2006/6/30&pages=A1&seq=2
    http://gpu-fun.spaces.live.com/PersonalSpace.aspx?_c01_ListID=cns!FB5EEACE075E1350!119&_c=links:119
    http://www.beyond3d.com/forum/showpost.php?p=788469&postcount=361
    http://www.theinquirer.net/default.aspx?article=33260
    http://www.extremetech.com/article2/0,1697,1987258,00.asp
    http://translate.google.com/transla...27/kaigai291.htm&langpair=ja|en&hl=en&ie=UTF8
    http://www.beyond3d.com/forum/showpost.php?p=804990&postcount=485
    http://www.beyond3d.com/forum/showpost.php?p=805099&postcount=493
    http://www.forbes.com/2006/08/18/nvidia-0818markets10.html?partner=yahootix
    http://www.beyond3d.com/forum/showpost.php?p=828033&postcount=688

    Update 9/12/2006: CW seems to be looking 600-700mhz core.

    http://www.theinquirer.net/default.aspx?article=34319

    48ps confirmed, here, follow the link download "graphics track": http://www.beyond3d.com/forum/showthread.php?t=33605

    Update 9/18/2006: VR-Zone takes their shot at immortality as either prophets or buffoons: http://www.vr-zone.com/?i=4007

    Update 9/29/2006: Some interesting pics here, including 12 memory chips, indicating the likliehood of a 384-bit memory bus and 768MB framebuffer: http://www.beyond3d.com/forum/showpost.php?p=841400&postcount=620

    Update 10/05/2006: DailyTech mostly confirms VR-Zone's specs: http://www.beyond3d.com/forum/showpost.php?p=845779&postcount=802


    *Added the "u" to rumours for our Brittanic overlord. :smile:
     
  2. Nick

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    G80 is new and improved? Wow I didn't even see the old one. ;)
     
  3. trinibwoy

    trinibwoy Meh
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    Complicated thing, that english language eh? :lol:

    I have to say though - you know you're at a quality establishment when the rumours thread is so well structured :D
     
  4. Geo

    Geo Mostly Harmless
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    There! :razz:
     
  5. Tim Murray

    Tim Murray the Windom Earle of mobile SOCs
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    I still think GDDR3 plus a 512-bit bus is way more likely than GDDR4 on a 256-bit bus. (Take what they did during the NV30 era and reverse it!)

    Okay, I guess I should elaborate. Given that ATI is already using GDDR4 and at the moment, only Samsung is producing GDDR4 in quantity, it would be foolish to assume that supplies would be plentiful enough to risk the G80's performance on its availability. With R580+ showing a nice jump in performance due to increased bandwidth, I think we can assume pretty easily that the next-generation chips, with geometry shaders and a ridiculous amount of fillrate compared to G71/R580, need as much bandwidth as possible. So... hooray 512-bit bus.
     
  6. Geo

    Geo Mostly Harmless
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    Did you read the last two pages of the previous thread, sleepy-head?
     
  7. Tim Murray

    Tim Murray the Windom Earle of mobile SOCs
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    You know I don't do that. But okay, not a lot of GDDR4 floating around, hooray, I was right.
     
  8. Farid

    Farid Artist formely known as Vysez
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    According to some extremely talkative little bird

    The bus width of G80 is interesting, as much as the number of RAM chips present on the board...
     
  9. nAo

    nAo Nutella Nutellae
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    This is not a rumour but since NVIDIA has a couple of patents about this I suspect G80 might use its PS units to perform blending operations between incoming fragments and the frame buffer.
    Basicly, even though D3D10 does not expose this AFAIK, PS units would be able to issue a special instruction which fetches into some registers all the subsamples colors potentially covered by a fragment and then blend them in the pixel shader.
    A 'smart' driver would be able to dynamically patch a shader everytime we change blending modes.
    I'm not saying that's easy to implement in hw (there are obviously some serious coherency/processing order issues to solve first :) ) but it would be nice in the future to have completely programmable blending modes at some point in the future :)
    It is also quite straightforward to expect more and more fixed function units to be slowly phagocytized by programmable units as we have more of them and more complex/more powerful/more accurate ALUs

    Marco
     
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  10. Sunrise

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    I don´t get one of Jen-Hsun Huang´s little sneak-peeks out of my head. Some months ago, he said something like: "With our next-generation graphics architecture, we want to further increase programming flexibility" and actually i´m still wondering what exactly he had in mind when he specifically mentioned "flexibility", while he was speaking a little about their future plans. Along with Jen-Hsung´s saying that "they want to innovate where it makes sense, instead of innovating like crazy" (like they did with NV30), i keep questioning myself what exactly would make sense here and in the future, WRT their first incarnation of a part that has to have enough potential to be at least worth another 2-3 years.

    We´ve already seen some patents, but i´m still at a point where i can´t really see what he may have meant by that. Maybe i´m reading a little bit too much into it, but if there are any ideas, don´t hesitate to post them here.
     
  11. trinibwoy

    trinibwoy Meh
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    Well that would be nice. One less client (ROP) to worry about when configuring the MC and you could probably do whatever floats your boat when it comes to AA.

    Actually in a situation like this would the PS need its own link to the memory controller or will it go through the TMUs (whatever those might look like) ??
     
    #11 trinibwoy, Sep 11, 2006
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  12. Sunrise

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    One of the questions that comes to mind is, how exactly will it work? Looking at current PCB designs there is no place at all for 2 more RAM chips on one side (well, physically there is, but you would need to increase the PCB either in length or put them at the back) because you have to keep in mind that there is a limit as to how close you can put them against each other (because of termination, etc.) and when you place them further away this could lead to some potential problems. There is a reason why 8 chips per side is the maximum right now. You´d need a fair amount of intelligent pathing when only 2 modules are placed further away.
     
  13. Razor1

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    Hmm interesting. I would think the same, a more programmable AA engine.

    Not sure but if PS would go through the TMU's wouldn't that lock the TMU's? I think they would need thier own connections to the memory control.
     
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  14. _xxx_

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    128 bits wide?
     
  15. Brimstone

    Brimstone B3D Shockwave Rider
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    My guess.

    G80 is two g70 improved cores with geometry shaders added to the architechture. Improved A.A. and HDR support along with other tweaks.


    The Sony PS3 RSX is comprised of just one of these cores.Two cores would require too much power and produce too much heat in a console form factor.
     
  16. zsouthboy

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    G80 has been in development much too long to be as simple as two G70s slapped together.
     
  17. zsouthboy

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    I know it's not true, but I'll put it out there:
    two PCB design?
    like the 7950, only one board is all RAM?
    obviously expense is a huge issue with that, etc.
     
  18. trinibwoy

    trinibwoy Meh
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    I hope your guess isn't based on anything to do with consoles, RSX or PS3 - or is it the GX2 that's leading you down that path?
     
  19. trinibwoy

    trinibwoy Meh
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    You could certainly make a case for dedicated framebuffer space/bandwidth on a high-end card given today's resolutions and HDR/AA requirements. You wouldnt have the crossbar complexity that sireric described earlier and it may even simplify accesses for the other clients like the TMU's. That's assuming that you can keep that dedicated bus saturated enough to justify its existence.
     
  20. Pete

    Pete Moderate Nuisance
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    Nice summary, geo. Kind of horrible to think we can deflate 29 pages into close to 29 words. :lol:

    Should we also add 600+MHz and maybe even accept a 384bit bus, given trumphsiao's chirping in the penultimate page of the previous thread? He's been right before, IIRC. The "4:1 concept architecture" is the most interesting part. Are we talking 48 PS "processors" : 16 ROPs in G80 (assuming it still has discrete ROPs)? Are we talking 64 PS ALUs : 16 ROPs in R600, assuming an extra PS ALU per "pipe" (though I'd expect this at a very high core clock)?

    (Or does G80 stick with 24 pixel shader "pipes/processors"--two DX9 PS ALUs each--but add two extra DX10 PS ALUs each? Nah, too NV30ish, if it's even possible.)

    I've also heard 16 VS/GS processors, too, though I forget where (possibly in one of the OP's links).

    48 pixel shader "processors" at 600+MHz sounds power and transistor hungry to me, weakly corroborating other rumors and perhaps hinting at 96 PS ALUs. It also makes Brimstone's "two G70s" theory not incredibly far-fetched, also considering 16 VS/GS shaders. That's twice a G70 in G70 terms, but obviously NV's been modifying the heck out of everything, so obviously it's not that simple.

    What does the rumored new AA engine signify, updating the ROPs or folding them into the PSs?

    Finally, nAo's talking about this, right?

    I've been out of the loop awhile, thus the more-than-usual silly questions.
     
    #20 Pete, Sep 11, 2006
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