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more info regarding PlayStation3's NV47-based RSX graphics processor

Discussion in 'Nvidia' started by AirRaid, Mar 30, 2006.

  1. AirRaid

    AirRaid Guest

    http://beyond3d.com/#news29579

    Playstation 3 RSX Graphics is NV47 Based
    30-Mar-2006, 01:11.59 Reporter : Dave Baumann

    It's long since been known that NVIDIA will be providing the graphics
    processor for Sony's Playstation 3, otherwise known as the RSX
    "Reality Synthesizer". While the expectation has been that it would be
    of a similar configuration to NVIDIA's G70 chip, powering the GeForce
    7800 series, a precise answer as to its composition has never been
    given before. However, accordingly to an article at
    watch.impress.co.jp, which has slides from Sony's GDC briefings, RSX
    is confirmed as being "NV47" based.

    NV47 is actually the previous codename for G70 - in fact development
    tools still list G70's codename as NV47 rather than G70. The graphics
    slide also highlights that RSX has 24 texture units, which is
    consistent with G70. Given the architecture of NVIDIA's G7x series,
    this indicates that RSX will also have 24 fragment shader pipelines
    with two ALU's per pipeline.

    This may also give some clues to why NVIDIA sought to release G71 in
    the configuration that it has, with the same pipeline counts as G70,
    rather than opting for a chip with more pipelines as the popular
    speculation indicated prior to G71's release. It is likely that much
    of the 90nm optimisation undertaken with G71 was to cut down on
    duplication on the work being carried out on RSX.

    The other, known, primary differences between G71 and RSX is that the
    PC's PCI Express interface will be replaced with a FlexIO interface for
    communication to the Cell processor, and RSX will only use a 128-bit
    bus, rather than a G71's 256-bit interface. Given the memory bandwidth
    difference between RSX and the PC versions, it begs the question as to
    whether RSX will retain all 16 of G71's ROP's. With the previously
    stated 700MHz memory speeds for RSX it will end up with the same local
    bandwidth as NVIDIA's mid-range GeForce 7600 GT, but also has to
    contented with twice the texture consumption (when sampling from
    graphics RAM) and pixel processor capability - it may not be much of a
    surprise if RSX enables 8 ROP's as opposed to the full 16 of G71

    ____________________________________________________________

    some technical slides from fairly reliable Japanese tech website:

    http://www.watch.impress.co.jp/game/docs/20060329/3dps3.htm

    PS3's RSX GPU is indeed based on NV47. Nvidia calls NV47 the G70
    (GeForce 7800 GTX)

    and the newer, more refined, speedbumped version of NV47 @ 90nm which
    Nvidia calls G71 (GeForce 7900)

    http://www.watch.impress.co.jp/game/docs/20060329/3dps309.jpg

    the G70, RSX and G71 are *all* NV47-based GPUs, they are *all*
    refreshes of Nvidia's 2-year old graphics architecture, the NV4X,
    which was first seen in the NV40 (GeForce 6800).

    none of these ( NV47-based G70, G71 and RSX) are true next-generation
    GPUs dispite what the deceptive people at Nvidia would have you
    believe.

    Nvidia's real next-generation GPU, the NV50, which Nvidia calls G80,
    will probably be seen by the end of this year, or around the time that
    Windows Vista shows up.

    Nvidia has been working on the next-generation NV50 aka G80 since
    2002..WHICH MEANS that the older NV4X architecture (NV40, NV47/G70/G71
    and RSX),
    I mean the fundamentals of which, Nvidia was probably working on in
    2000-2001.

    the RSX obviously has some new pieces in it that help it work
    effectively with the CELL processor and Rambus XDR memory, and other
    parts of the PS3, but in NO WAY is RSX a next-generation GPU.

    Yet, there is another thing to concider, as the Beyond3D and other
    articles point out -- in some areas, the RSX has LESS performance than
    even the PC versions of NV47 / G70 / G71. because RSX only has a
    128-bit interconnect to memory (the PC versions have 256-bit
    interconnect to memory) and the RSX probably (I said probably) has
    HALF the amount of ROPs ( the backend raster parts) than the highend PC
    versions.

    the ATI Xenos GPU in Xbox 360 only has 8 ROPs, and I expect no more in
    RSX.

    from everything known about RSX, it does not seem like it will be much
    better than the Xenos GPU in Xbox 360. -- Both the RSX and Xenos will
    have some advantages and disadvantages compared each other.
     
    AirRaid, Mar 30, 2006
    #1
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