How to copy networked files at maximum speed despite listening to audio

Discussion in 'Performance & Tweaks' started by Jason, Oct 17, 2007.

  1. Jason

    Jason

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    <P class=MsoNormal style="MARGIN: 0in 0in 10pt">Windows Vista uses a new service called Multimedia Class Scheduler Service or MMCSS which runs under svchost.<P class=MsoNormal style="MARGIN: 0in 0in 10pt">This new service is used to boost performance whena multimedia application begins playback, the multimedia APIs it uses call the MMCSS service to boost the priority of the playback thread into the realtime range. This creates for a seamless playback without those annoying glitches in music when you are doing heavy duty computing at the same time.<P class=MsoNormal style="MARGIN: 0in 0in 10pt">Tests of MMCSS during Vista development showed that, even with thread-priority boosting, heavy network traffic can cause enough long-runningcpu interruptsto prevent playback threads from keeping up with their media streaming requirements, resulting in glitching. MMCSS’ glitch-resistant mechanisms were therefore extended to include throttling of network activity. It does so by issuing a command to the NDIS device driver, which is the driver that gives packets received by network adapter drivers to the TCP/IP driver, that causes NDIS to “indicate”, or pass along, at most 10 packets per millisecond (10,000 packets per second). <P class=MsoNormal style="MARGIN: 0in 0in 10pt">This loss can be up to 15% on a gigabit network. <P class=MsoNormal style="MARGIN: 0in 0in 10pt">The Tweak:<P class=MsoNormal style="MARGIN: 0in 0in 10pt">Now you can't just disable the MMCSS service since windows audio is dependent on it. In other words disabling it means no sound for your computer.

    So I ran regedit (type regedit in the start menu search box), and navigated and changed the key:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Audiosrv\DependOnService

    Now remove MMCS from that key in the list, and set MMCS to disabled in services (type services in the start menu search) Now reboot!

    As soon as I rebooted I was able to copy files at 40mb/s+ while listening to audio

    Example of priority boosting by Vista:<P class=MsoNormal style="MARGIN: 0in 0in 10pt">[​IMG]

    Example of network throttling:<P class=MsoNormal style="MARGIN: 0in 0in 10pt">[​IMG]
     
    Jason, Oct 17, 2007
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