netkas.org

Just thoughts

Currently,  the onyl advantage of gaming consoles is huge cpu-gpu interconnect bandwidth:

PS3:  Cell FlexIO bus interface
20 GB/s read to the Cell and XDR memory
15 GB/s write to the Cell and XDR memory

XBOX360: 21.6 GB/s front side bus

10.8 GB/s upstream and downstream

it looks huge (especially ps3)  in comparision with pci-express 2.0 x16

which is 8GB/s upstream and 8GB/s downstream. It isn’t bottleneck in current game’s developing paradigm because it was created to workaround that bottleneck in ages of pci-e 1.1 or even agp. Just compare 2gb of vram on 6970 and 256mb vram on ps3. Cell cpu in ps3 can quickly feed gpu with needed data without the need to store everything in vram to keep up with fps. On pc, for sake of speed you gonna store as much as possible in gpu’s vram. (Yeah, I understand the difference in the output resolution, but still..)

But, next generation of pc gonna fix that, there is already a lot of pci-e 3.0 mainboards you can see on computex these days. Its gonna be released when sandybridge-E and ivybridge will be launched.

Pci-e 3.0 gonna give us 16 GB/s downstream and 16 GB/s upstream, which is now comparable to ps3.

I just wonder what game developers can do if they will not care about backward compatibility and will fully use that 32 GB/s (total bandwidth) line.

Comments

  1. m
    June 1st, 2011 | 12:05 am

    Backward compatibility prob won’t be a factor in holding back games, they are already restrained by the business aspects of the gaming industry. I don’t want to say PC gaming is dead, but it’s not what it once was.

  2. Jumpy
    June 1st, 2011 | 11:31 am

    Console Gaming can’t even begin to compare to PC Gaming. PC Gaming is every evolving and moving forward. Each time a new Engine is released with a new Game with awesome new Effects, it just totally slaps our current (out-dated) Consoles in the face.

    Consoles simply aren’t upgradable, and that holds them back. PCs on the other hand have so much freedom.

  3. Roger_CWB
    June 1st, 2011 | 12:45 pm

    It’s good, but I still prefer to wait for the next generation of consoles, I want to play Crysis 2 in the console with the same graphics as the one top PC has.

    And if you think, when CryEngine was released, he was told it would never run on consoles and now we have Crysis 2, ok, the graphics is not the same as a good PC, but is running on a console with 6 years old graphics card hardware.

    My PC still will be just for hackintosh purposes. 😉

  4. HotSix
    June 1st, 2011 | 1:13 pm

    Since I can remember, bandwidth (be it CPU RAM or GPU RAM) was always THE bottleneck. A direct, hyper fast IO bridge would solve so many problems. Allowing transfers of compression free high resolution graphics would not only bring a HUGE performance boost, it would also allow smaller CPU/GPU boards with less power consumption and less heat.

    32GB/s is better but still not enough to allow compression free high resolution graphics.

    Wonder when we’ll see the first board architecture designed with that in mind.

  5. von Matterhorn
    June 1st, 2011 | 1:34 pm

    Bandwith is not the problem.
    DirectX is the problem. the abstraction reduces the effectiveness of game engines. opengl would be much better, but not as good as a console: a console can be programmed directly because there’s just one graphics card to support. even look at the iPad: the hardware is’n very powerful, but the restriction to one graphics card allows pretty impressive graphics for such a device. graphics cards in pcs are too different to effectively support them.
    the other thing is business: the revenue of console games is much higher than of pc games. so the industry just produces console games and ports them to pc.

  6. vicious
    June 1st, 2011 | 3:12 pm

    Thanks for sharing your thoughts netkas. I agree with ya.

  7. Stanly.ok
    June 1st, 2011 | 4:28 pm

    Привет, Netkas! There is a video on youtube with HD 6990 running through PCIe 16x, then 8x and finally at 4x

    http://youtu.be/vfXALgE7mVM?hd=1&t=1m10s

    To make the long story short – only PCIe 4x creates bottleneck of just 10-20%! So the only thing holding game developers back is the consoles 😀 why?

    Primal interest are the consoles, because games are hard to steal
    Second – PC’s, because there is DirectX, which makes a game development easier, making up for easy-to-steal environment
    Last, but not least – Mac’s – no game APIs, end of story (=

    P.S.: bandwidth comparison: PCIe 3 8x = PCIe 2 16x, but even the fastest modern two-GPU videocard can’t outperform PCIe 16x … (=

  8. mozo
    June 1st, 2011 | 6:51 pm
  9. netkas
    June 2nd, 2011 | 4:29 pm

    They can’t outpefrom PCIe 16x cuz developers does it that way. I saw devs complaining they cant do as much draw calls to gpu on pc as on consoles

  10. Lama
    June 3rd, 2011 | 2:37 pm

    Great article, How does AMD’s Fusion with PCIev3 help in this situation? since they’re going to have CPU+GPU=APU there…

    ///Liano’s gpu isnt that great in terms of performance and main limiting factor there is memory bandwidth which is shared with cpu and is just 128-bit ddr3

  11. Stanly.ok
    June 3rd, 2011 | 4:33 pm

    if that’s the case, then PCIe 3.0 won’t solve the cause, right? (= why do they introduce it then? I believe that software optimization is the reason …

    you’ve probably heard about soft-modding GeForce into Quadro? it bumps up the performance in professional software! gaming degrades though … proving the point that it is all about developers, drivers, APIs and software running on top of it*! I bet if Crytek had no interest in consoles, the final version of the game would’ve been even more impressing 😀

    *I do understand, that for example GTX580 runs much better, than GTX460 with same quality of software optimization (=

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