PS3 vs 360 Drive Speed Question

Discussion in 'Console Technology' started by Blade47167, Jun 20, 2007.

  1. Blade47167

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    2x Blu-ray Drive (72Mbps(9MB/s))
    Single Layer (2x CLV) - Constant Linear Velocity (Same speed across entire disk)
    Double Layer - Couldn't find any data but no games have been released on a double layer yet.

    Entire Blu-ray Disk is read at 9MB/s.

    12x DVD-Rom Drive SL (9.25MB/S-15.85MB/s(AVG ~8x(10.57MB/s) DL (4.36MB/s-10.57MB/s(AVG ~6x(7.93MB/s)
    SL(DVD-5) 12x Max (5-12x Full CAV) - Constant Angular Velocity (Speed Varies from edge to edge)
    DL(DVD-9) 8x Max (3.3-8x Full CAV) - Constant Angular Velocity (Speed Varies from edge to edge)

    SL DVD is 1.57MB/s > SL Blu-ray
    DL DVD is 1.07MB/s < SL Blu-ray

    Majority of 360 games are on DVD-9.

    Sources:
    Hitachi 12x DVD-Rom Faq (Page 2)
    http://www.hitachi.us/supportingdoc...500,0.pdf#search="Hitachi 12x dvd read speed"
    What is DVD?
    http://www.videohelp.com/dvd
    Blu-ray.com Blu-ray FAQ
    http://www.blu-ray.com/faq/
    Wikipedia - Constant Linear Velocity
    http://en.wikipedia.org/wiki/Constant_linear_velocity
    Wikipedia - Constant Angular Velocity
    http://en.wikipedia.org/wiki/Constant_angular_velocity

    So anyway I did some research and I really just want to know if there is an truth to this or do I have it all wrong.
     
  2. -tkf-

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    I checked up on severeal DVD Drive reviews and i found that in average the DVD Drives even in SL mode had a problem matching the constant speed from the Blu-Ray.

    The Developer on the 360 will have to place their content carefully or just go for the low speed.
     
  3. Jesus2006

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    These numbers are correct.

    There are however still games on single layer DVDs on the 360, but i'm pretty sure those will be very few in the future (as games grow larger and larger on those discs).
     
  4. inefficient

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    The 360's that come with a Hitachi DVD drive apparently use the "GDR-3120L" model.

    The PDF you have is for the GD-7500. Are we sure the performance is similar? Because otherwise the performance of DL discs seems so poor that devs might just be better off using 2 SL discs.

    From their website it does seem like the GD-7500 line is the "latest" version and the GD-3xxx line has been discontinued for retail. So it does seem unlikely the 360 drive would perform any better than the GD-7500. But still I'm just saying the paper does not match the HW.
     
  5. Mmmkay

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    I'm not too sure about these numbers. Each layer on a 360 disc has 3.4GB of usable space, where this is positioned on the physical disc and how the data is arranged in the space will both have an impact on average read speeds. It has also yet to be adequately evidenced in my opinion that the 360 suffers from lower performance on the second layer. Not only are the drives not (or at best variants of) commercially available drives, but things like read speed are governed by firmware not model number. These numbers (for the first layer) are also somewhat contradicted by Fredrik Lonn of Avalanche (Just Cause), who claims that in lieu of seek times, a safe estimate for read speed should be 10MB/s.

    http://www.gamasutra.com/features/20061130/lonn_01.shtml
    Which brings me to my next point of contention, these figures are idealistic in that they require sequential data. They do not take into account seek times, which are crucial in sustaining data throughput. What a Blu-ray drive (if it does genuinely operate in CLV for games) offers in consistency it loses out on seek times.
     
  6. Rangers

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    Then why have several devs stated 360 drive is faster?

    I dont have the links but I know I have seen it stated a couple times.

    Also yeah, a CLV has slower seek times. In fact, the throughput of a 12X DVD and a 5400 RPM drive is similar, the only great advantage of the HDD is in seek times.
     
  7. Cheezdoodles

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    Your also forgetting that game discs are mastered. The files your loading the most will be on the outer rim, to get maximum speed. The averages listed here, would only be correct if we loaded a full dvd9, 1 time per file. But thats not happening in real life, your loading some data more often than other data.
     
  8. DJ12

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    In an ideal world that would be the case, but how many devs really spend much thought on file distribution?

    Some games on PS2 were shockingly bad and the early 360 games I had, the majority of them were constantly "seeking" after a short bit of loading.
     
  9. Todd33

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    I can't say how the two compare in load times on average (Motorstorm is bad though), but the noise generated is a huge difference. I'd love the option for a low RPM mode on the 360, I can live with longer loads so I can hear my games (play at night).
     
  10. Tap In

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    headphones :wink:

    I need my game sounds to rattle my ears :cool:
     
  11. infinity4

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    what about headsets which i am sure most of 360 owners use here ;)
     
  12. cthellis42

    cthellis42 Hoopy Frood
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    You have any links for that? I like real-world sampling, and sadly one gets damn few examples of it.
     
  13. Todd33

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    Ya, I do need a pair for my receiver. I wonder if my PC USB ones would work in the 360? Though I play a lot of my 360 games co-op with a phone headset on.
     
  14. betan

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    People who assume constant read and seek times for BDs are forgetting Resistance has a lot of garbage data on disk.
    I also remember reading that Insomniac guys burned lots of disks to get optimum access time and in order to do the tests more quickly they removed PAL videos from the game.
     
  15. Blade47167

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    I knew about the seek times. I believe thats why the Oblivion game has duplicated data to help improve seek times. But once the data is found the game tends to load faster than the 360 version.

    Also alot of it is put on the outer edge of the disk yes but thats still only 1.5mb/s faster if my numbers are right. And for just how much of the outer edge I'm not sure.

    So your saying that the 360 DL disks are limited to 3.4GB per layer? I didn't know that I thought they were full DVD-9s. Perhaps they make it this way for a reason since the inner most part is so slow. That would make the data start about 1/4th of the way into the disk right?

    I just looked up the Gears of War Image size and it comes in at 6.4GB. I'm assuming alot of that is texture data. But how much of it is actually on enough of the outer edge to actually go faster?.

    I know the unreal engine using streaming so would a constant speed be more beneficial?
     
  16. Darkon

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    No, 420MB per region
     
  17. betan

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    I assume your objection to my use of a relative term stems from the early padding reports which claimed most of the data was garbage. It has nothing to do with what I wrote, and even half a gigabyte is a lot of data for me (admittedly though I thought it was around two).

    That said, I cannot help but wonder though what you mean by "per region"
    Is padding region locked now? :) What does region even mean?
     
  18. Phil

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    I'm not sure I fully agree. Comparing identical cases, one can assume that identical content on both disks would cover a smaller area on the Blu-Ray disk compared to on DVD. That would imply that seek times would be at worst comparable, at best better on BluRay.

    I.e.: You have a game that fills the entire DVD (single layer) - it would fill less than a fifth of the physical area on a Bluray disk, which ultimately means the laser has to travel less area to fetch data across the used space.

    In ideal situations, the additional space on Blu-Ray could be used to arrange data across the disk to improve seek times.

    :idea:
     
  19. Mmmkay

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    >.<
    32MB spacing each FMV. That's all.

    Yeah, I think you're right. It's something I hadn't considered. The metric for determining a seek time will probably be calculated relative to the entire disc surface. So while Blu-ray may have a general slower seek time, an indentical case comparison between a DVD-9 and BD-ROM would probably give a more favourable figure. It's an interesting scenario I would like to see benchmarked.
     
    #19 Mmmkay, Jun 20, 2007
    Last edited by a moderator: Jun 20, 2007
  20. Blade47167

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    I would also liked to see it benchmarked. The first thing I remember reading was how the Blu-ray was inferior to the 360's DVD drive but from these facts thats just doesn't appear to be so. Especially if all developers get to the point were games are streamed like Lair.
     

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