X1800 XT makes the case...

Discussion in 'Architecture and Products' started by scificube, Oct 4, 2005.

  1. scificube

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    In an effort to support only FP32 and no partial precision (will almost) it seems ATI efforts in restructuring the HW in order to make this a reality has reaped some some nice rewards.

    http://www.techpowerup.com/reviews/ATI/R5XX/3

    With only 16 pipes...arrays or 4 quads or however things are best described nowadays it seems ATI has made a strong argument for it's ultra-threaded approach to things considering it outperforms the 7800GTX which has 24 pipes.

    What is equally as interesting to me is that ATI mentions that the architecture is "ideal" for physics. This would appear to be a shot over Aegia's bow if ATI is to be believed. I don't believe this architecture could handle the tasks of rendering and physics at the same time, but this would still seem an intentional warning shot or at least an invitation to play around and see what one could do...at least with offline rendering perhaps.

    I have to say I think something either is seriously wrong or seriously interesting is going on with the fear single player demo. Safe bet...something is borked.

    edit:
    better wild theory - Fear utilizes parallax mapping. ATI mentions the architecture is well suited to handling parallax occlusion mapping with SM3.0...seems ATI may be quite right :)
    end edit:

    What say you...

    Is the performance advantage due to ultra-threading? (in having fewer pipes a higher clockspeed and more bandwith would bring one back to even, but would it be enough to seriously outperform the 7800GTX?)

    What do you make of the physics quip in the chart?

    ATI makes some bold claims in being able to use various methods to do HDR with MSAA while real men use FP32 to get manly results with SM3.0...ATI isn't just blowing smoke up our collective...well you get my drift. I think I'd like to wait for some collaboration of these numbers but the physics quip was something I thought was interesting. Any substance to this...or no?

    In both the X1800 and Xenos being ultra-threaded so to speak if the numbers are to be trusted then if nothing else does this not bode well for Xenos?

    Please discuss.
     
    #1 scificube, Oct 4, 2005
    Last edited by a moderator: Oct 4, 2005
  2. Skrying

    Skrying S K R Y I N G
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    Your bring up an interesting point. But one question, if the R520 can be used to offload the CPU for physics, then why not a bit more improvment in a physics heavy game such as HL2? Does it need to be implemented in the engine by your guess?
     
  3. scificube

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    Actually I just tossed the idea that physics was being offloaded to the GPU with Fear. That would have required ATI and the Fear crew to trust each other a good deal to say the least. It was wild speculation on my behalf.

    What seems more plausible is that the architecture is somehow better tweaked to handle parallax mapping better and Fear uses this technique to represent damage your gunfire can do to the enviorment in the single player demo.
     
  4. KimB

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    Let's wait until we see some independent reviews before making absolute claims on performance levels. Two days isn't that long.
     
  5. Skrying

    Skrying S K R Y I N G
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    Yet another interesting idea, and one that seems much more plausible and likely to me. But do you think it could make up that much of a difference, because the slides show a huge one to say the least.
     
  6. scificube

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    I'm betting it makes a good difference but THAT big a difference is something...well special.

    Chalnoth is probably right. It may be best to wait and see with this stuff. I was seeing if anyone had noticed what I had noticed. 2 days in truth really isn't that long to wait...it's a good thing I know that now. Does everything happen while I'm asleep? Sheesh.
     
  7. KimB

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    Yes, but there have been a number of situations in the past where a huge difference between two cards has been measured, but it turned out to be an error on the part of the person running the benchmarks. So independent results are really necessary to be certain.
     
  8. Skrying

    Skrying S K R Y I N G
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    You're taking all the fun out of this!
     
  9. trinibwoy

    trinibwoy Meh
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    Damage control?
     
  10. digitalwanderer

    digitalwanderer Dangerously Mirthful
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    Nah, Chal is actually right. Wait until we have some numbers from a number of places on a number of things before you start projecting too much. ;)
     
  11. KimB

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    I'm just taking this from the perspective of a scientist. You really have to have independent verification to be sure of the results of any experiement.
     
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  12. TheAlSpark

    TheAlSpark Moderator
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    Should the Fear performance be representative of Doom 3's performance :?:
     
  13. digitalwanderer

    digitalwanderer Dangerously Mirthful
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    No.
     
  14. Skrying

    Skrying S K R Y I N G
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    I know. And in all seriousness this is how I approuch things like this, though I really enjoy speculation sometimes. I was joking with you. :p
     
  15. Geo

    Geo Mostly Harmless
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    Have we not got tired of "pipes matter" yet? :sad:

    Maybe we ought to be comparing performance/per transistors? Except apparently we can't really do that either.

    So we have to compare die size and adjust for known process differences and compare performance/per normalized mm2?

    But if there was any shred of "pipes matter" left it should have gone out the door last night --even if R520 doesn't have decisive performance advantage; I can't imagine at this point it will have decisive performance disadvantage. . .and clearly the mhz difference will not make it up if "pipes matter".
     
    #15 Geo, Oct 4, 2005
    Last edited by a moderator: Oct 4, 2005
  16. KimB

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    Well, there's a lot of things to compare.

    Performance/cost (end-user cost)
    Performance/watt (important for overclocking)
    Performance/transistors (not really directly useful, but interesting in investigating the efficiency of an architecture)

    And, of course, absolute performance is always a fun thing to measure for the top of the line products.
     
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  17. Geo

    Geo Mostly Harmless
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    At this point you put any trust at all in a comparison that relies on transistor count as a divisor? Not I; thrown in the towel on that one for now.
     
  18. KimB

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    Well, it can be important as an indirect measure of cost. Better is performance per die area, of course.

    Anyway, I'm willing to bet that the majority of any efficiency improvements that we see in the R5xx core are due to the disassociation of the texture units from the ALU units. I think that once we have the cores and can do decent measurements of performance per die area, we can get a better idea of whether or not this was a good thing to do.

    For example, if we assume that the R520, at a clockspeed where the power consumption is roughly on par with the G70, is 15% faster, but is also 15% larger than a 90nm G70 (which doesn't exist, so we might use transistor count for a placeholder), then we might assume that the choice to go with disassociated units really was a wash, and its only real benefit is better branching performance.

    If, on the other hand, the R520 is released, and at a clockspeed where the power consumption is roughly on par with the G70, is 15% faster, but has about the same number of transistors, then we can roughly conclude that the choice to go with disassociated units was, in general, a good decision.

    As a side comment, I don't feel the ring bus has much of anything to do with efficiency for current games. I feel that it is most likely an efficiency improvement in terms of sharing the texture units with the vertex units, and I doubt it helps at all with the efficiency of any current game implementations of SM3.
     
  19. Acert93

    Acert93 Artist formerly known as Acert93
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    I am hoping reviewers spend as much time judging IQ as they do performance. IQ can be hard to qualify, but I am interested in how MSAA+HDR performance and looks, the new angle independant AF, Adaptive AA, etc... all work out in practice. On a $400+ card you expect Good IQ and Good Performance.

    If you only wanted good performance you could get a 6600GT and turn off all the features (i.e. low everything) and run at a stead 60fps in every game I know of. I know last summer when I bought my NV40 I was looking for that killer combination of Performace+IQ. If I had not I would have stayed with my Radeon 9700 which performs well to this day if performance is the only thing you were after.
     
  20. overclocked

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    I would add time to market ala instant launch also in that formula, not in general but comparing just the case with G70/R520.
     
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