Nvidia added PCI-E data compression.

Discussion in 'RivaTuner Advanced Discussion forum' started by Khenglish, May 12, 2011.

  1. Khenglish

    Khenglish Master Guru

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    Starting with at least the 258 driver series, if not earlier, Nvidia added a compression algorithm for PCI-E data. This algorithm only activates if a modern Intel IGP is installed, an Optimus enabled driver is installed, an x1 link is present, and a fermi based GPU is installed. As seen here, this compression allows an external graphics card connected to a laptop with only an x1 link to achieve acceptable performance.

    Unfortunately, this algorithm only activates for a small set of hardware, while many others could see major benefits from it. I posted here because Unwinder was known for some time to be the king of knowledge of Nvidia graphics drivers, and the surrounding community was also knowledgeable. I am hoping that someone may have an idea of where to look in the registry to force this compression to activate. I tried looking some myself, but I have found that Nvidia seems to put its registry keys all over the place, and I really don't know what I'm looking at or looking for.

    Note that all Nvidia drivers have this compression code in them. Any Nvidia driver can be turned into an Optimus driver by added a few lines to the .inf prior to installation. I do not know if the code is present or not if the driver did not have these lines added.

    So if one of you has an idea on what to do to force on this compression, any help would be appreciated.

    Thanks for reading.
     
  2. stone-eye

    stone-eye Master Guru

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    Well I know I read that Nvidia are supposedly bringing a form of optimus to desktops.

    http://www.anandtech.com/show/4292/nvidia-synergy-desktop-optimus

    Maybe once this development is more mainstream it'll become easier to adapt. The compression (i believe) was developed specifically for the NG-ION bandwidth issues when connecting to the Intel Atoms frame buffer over a 1x PCI-E link due to Nvidia not having a license work any other way.
     
  3. Khenglish

    Khenglish Master Guru

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    A problem with just waiting for Synergy and hoping it's like Optimus is that currently the bandwidth compression will not work with an x2 link. It will only activate on x1. The workings of the compression is very unknown at this point and I can see Nvidia not supporting it at all in the future, or the means by which some people are enabling it may stop working with future driver releases.
     

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