Xbox One (Durango) Technical hardware investigation

Discussion in 'Console Technology' started by Love_In_Rio, Jan 21, 2013.

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  1. Cyan

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    Greenawalt hinted at the fact that you have to adapt your engine to the Xbox One in order to get the results, but as I said previously, if they can find a workaround for the bad design decisions behind the design of the console -64MB of eSRAM instead of 32 would have been the better choice-, you might be in for a treat.

    I think the Xbox One is an excellent console to achieve high framerates. (resolutions are an entirely different matter, lol)

    I kiiiiiiiiinda like the shoe metaphor Dan Greenawalt chose to explain himself.

     
    #7081 Cyan, Nov 14, 2013
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  2. Strange

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    We seem to forget that 32MB eSRAM already takes up ~60mm^2 or so and doubling that to 64MB may cause more problems to the already huge APU.
     
  3. (((interference)))

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    So anyone want to some up what the general sentiment here has been regarding the resolution downgrade on XB1?

    32 MB ESRAM not being big enough for 1080p rendering buffers?

    I think it's quite possibly mainly due to MS's tools/drivers being behind Sony's (as we've heard mentioned a few times before)

    As if it was just due to the ALU differences you'd expect XB1 to run at ~30% lower resolution .eg 900p rather than less than 50%...
     
  4. McHuj

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    It maybe tools, but I think the bigger culprit is a compressed schedule for launch games. Even if the tools were mature, it would still take a lot more effort to port existing engines to utilize it efficiently. You're probably better off building a new engine from the ground up for the console. That's something a multiplatform studio that's developing 5+ SKU's of game doesn't have time for this year.

    In terms of graphics, I actually think both console's exclusives look pretty damn good relatively to past launch titles.
     
  5. kalelovil

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    We also don't know precisely how the levels of API abstraction and OS overhead compare between the two machines and the impact this has.
     
    #7085 kalelovil, Nov 15, 2013
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  6. (((interference)))

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    True, it's likely the toolchain and the lack of time devs have had to familiarize themselves with the final system (since they've had numerous last minute tweaks) and figure out how to get their engine using the ESRAM properly.

    It's like the 360 launch, where PGR3, Perfect Dark Zero etc all resorted to sub HD framebuffers to fit into the 10 MB of eDRAM.

    I recall Richard saying that 16 ROPs would be adequate for 1080p and the PS4's 32 comes across as overkill? I don't really know either way myself.

    The PS4's GPU overhead is apparently in a 'similar ballpark' to XB1's, so I'm guessing between 5-10%.

    The XB1 API is definitely more restricted (since the game is running in a VM it talks to the hardware through the Host OS/hypervisor) but it wasn't supposed to be a big deal (though it's quite possible they haven't finished polishing the API or handed it over to devs quite late - meaning they haven't had the time to optimise for it).
     
  7. Strange

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    I honestly think it's not because 32MB eSRAM not being big enough for a certain task or not having enough bandwidth. The issue should be the the how the system's >50% bandwidth only serves 0.4% of the memory and how you can only do that much with 0.4%. So it's main problem is that it's not big enough to fulfill all the tasks the devs want it to fulfill under the condition that the rest of the 99.6% of the memory only has ~60GB/s to play with.
     
  8. SlimJim

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    Microsoft developed "Tiled Resources" just for that.

    As for high frame rates: the Xbox One could run games with complex, realtime lighting like DriveClub at 120fps, easily.
    Though it won't be at 1080P. or 576P for that matter
     
  9. Ceger

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    What's with all the replies and technological stabs in the dark lately across multiple threads?
     
  10. Laa-Yosh

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    I think you kinda misunderstood that comment. He means framerates and resolutions are a complicated issue.
     
  11. babybumb

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    Does Xbox have a separate realtime videoencoding chip?
     
  12. Kaotik

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    I'd guess it's much better option to just use VCE which AMD can provide :wink:
     
  13. Pixel

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    We are seeing memory bandwidth issues on X1 actually.
    This Forza direct feed gameplay video released today shows main memory limitations when streaming textures. A more realistic graphic representation than the videos showing the Autovista models actually racing around in the countless marketing videos being put out by their marketing division.

    They seem to be forced to use low res textures on the roof of the car & on the top of the trunk lid.

    http://www.youtube.com/watch?v=R8Sg6kmxYKY

    Gameplay looks great though.

    edit: You can see inside the cockpit they also use smart design to have low res textures here and there.
     
    #7093 Pixel, Nov 19, 2013
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  14. warb

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    That wouldn't be a memory bandwidth limitation, even if I could make out what you're claiming in the video. It'd be a HDD read speed, or memory quantity limitation (if high-res textures never popped it) not likely with 5GB.

    Edit: Got it to 1080p. The texture looks fine. It's probably the texture filtering making the steeply angled tops look softer.
     
    #7094 warb, Nov 19, 2013
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  15. taisui

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    So I see a bunch of issues with this clip, the compression is pretty bad, I think I am seeing interlace as well.

    I can't see the low resolution texture you are talking about, if you are talking about the environment reflection, well, they are usually lower resolution because all intermediary buffers are done in lower resolution to save computation.

    Last, I just don't see how you can jump from a youtube video to the conclusion implying bw limitations.
     
  16. Pixel

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    Its not an HDD limitation. Its not memory quantity either, there is plenty of memory. It would take an extra 20th of a second to load a slightly larger texture file since the file is being read sequentially off the HDD no extra seek time is involved. Not just loading screens, that ingame prerace cinematic is also another opportunity to hide the extra 1/20th of a second needed to stream the slightly larger texture file off the hdd.

    Some of the car textures may be stored in the esram since the framebuffer wouldn't take up the whole 32MB cache and they are reoccurring every frame. Unlike Ryse which is 1600x900 its possible that texture limitations had to be made because the framebuffer is slightly larger in Forza's case running at 1080p and there is only 16MB or less remaining to store the cars data.

    It would be wise to store the cars data in the esram in order to elevate memory bandwidth requirements on the main memory.

    Both consoles gpus have memory bandwidth limitations in comparison with current +$150USD discreet videocard equipped with gddr5.

    The videoquality certainly isn't the greatest given the compression, but since the car is still almost perfectly still in a few frames in straight portions of the racetrack, the compression on the car in those moments isn't too bad. You can see in those moments the textures on the spoiler and rear of the car are higher resolution than the roof of the car.
     
    #7096 Pixel, Nov 19, 2013
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  17. Cyan

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    Developers say that thanks to the huge amount of memory they have at their disposal compared to the previous generation, they only use one model for every car in the whole game.

    There are no LODs, according to them, and the cars in Autovisa are the same you have when you are racing. This goes for every car, so even CPU opponents are made from just one model.
     
  18. warb

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    The textures will be read from DDR3 though. A few inconsistent textures probably speaks more of time constraints or something else rather than memory bandwidth. I can't see how memory bandwidth would be the concern (for consistent textures on the thing that's always on screen in a racer). The game is 60FPS though.


    The design on top of the car looks softer because it's at a sharper angle. It seems fine at other times. Same texture, different angle and lighting.
     
    #7098 warb, Nov 19, 2013
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  19. ERP

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    Looking at the video, I'm not even sure the textures are lower resolution, if anything the issue if the filtering, looks like it could use a notch or two more of anisotropic.

    Besides that taking any one observation from any one games and extrapolating to some useful conclusion is at best wishful thinking.

    If I had to guess, the issues the ESRAM imposes is a combination of it being too small for a 1080P GBuffer with some of the more popular deferred rendering approaches. And having to arrange your rendering to ensure the right set of things are in it at the right times. ROPS could also be a factor, depending on the tile cache hit rate, but you can get a lot of overdraw with 16 ROPs at 1080P before it becomes an issue.
     
  20. taisui

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    I'd be surprised that Forza actually streams in car textures (which are needed at all time) versus streaming something in the background track, just saying. Besides, the need for streaming actually is a side effect of not having enough memory.

    I disagree, ESRAM should be used primarily for frame buffer since that's where most bw are spent.

    Car looks like crap, you feel it looks better because it's mostly red, but all the finer details are all gone due to the compression.
     
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