May 24 2008

How to Improve Network Performance in Windows Vista

network_sharing There have been many reports on the web about networking and Windows Vista and how slow it is when moving file between your computers, especially involving gigabit networks and also to a lesser extent 100 megabit networks. If you’re a regular reader you know we discussed some ways to improve this issue by turning off RDC Remote Differential Compression and it helped a little, but for the most part the problem remained, and I learned to live with it.

Then a reader named Tarrant1701 posted a comment in my follow-up post about RDC asking about his slow networking speeds on his gigabit network and we got into a Email discussion about various web pages we’ve come across and things to try to increase his speed, the culmination of which resulted in his finding a Microsoft Knowledge Base article number 948066 that describes the problem in detail and offers a solution to fix it.

Its seems the problem stems from Multimedia programs like Windows Media Player and Media Center requiring more network resources so Vista starts throttling network packets to restrict the processing of non-multimedia network traffic. Hear’s what MS has to say about it.

The throttling will come into effect only when you are running multimedia programs that are time sensitive. However, this throttling mechanism can potentially cause a decrease in network performance during the active multimedia playback period. This decrease in performance is likely to occur only on high speed networks that are saturated to maximum capacity.

But testing done by Tarrant1701 have shown.

if I have vista media center running in the background, then I get the 16 MB/sec transfer speeds. If i completely exit out of VMC and do another transfer, then I get 35 MB/sec!
somehow, having VMC running really slows down network transfers (even though VMC itself is not actively utilizing the network at all!)

The fix involves editing the Registry to turn off Network Throttling. As always create a System Restore Point to backup your Registry, then follow the steps below.

  1. Click the Start Orb and type Regedit in the search box.
  2. Click Regedit.exe at the top of the search results under programs.
  3. if you are prompted for an administrator password or for a confirmation, type the password, or click Continue.
  4. Navigate to the following key
    HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionMultimediaSystemProfile
  5. In the right hand pane double click NetworkThrottlingIndex and type in FFFFFFFF (that’s 8 F’s) in the Hexadecimal field.
  6. Click Ok and restart your computer for the settings to take effect.


I spoke to Tarrant1701 this morning to see if he was having any problems after about a week of use and he said

I’ve had no problems at all. Am able to watch DVR-MS files on the host HTPC and copy a different DVR-MS at 45 MB/sec to my desktop PC without any glitches.

As always your results may vary.

Microsoft says you can adjust the NetworkThrottlingIndex from 1 to 70 in the Decimal value with 10 being the default.

If you have playback problems in Media Center try adjusting the Decimal values.

in conclusion I’d like to thank Tarrant1701 for all the testing he done and help he’s provided.

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    8 Comments on this post


    1. E-M@iLinAtoR said:

      This Tip made my life worth living again 😀

      I was stuck to 9 MB/s while copying files from my Server and 13 MB/s while sending files to it since years.
      I always knew, it was a shitty bug, created by will by a stupid MS-Engineer putting that throttling feature in. That “dude” destroyed the nowadays most important part on a PC, the Network, by making a stupid mistake!

      Thanks to you guys, i’m back to normal again!
      My files come down or go back to my Server with 50 MB/s now!
      This will save me about 1h/day while stupidly waiting for copies from my Download Server, so i actually have more time to life now, lol. Before fixing that, it was slower than my former Win95 100Mbit network, i had 13 years ago!

      November 13th, 2008 at 7:15 pm
    2. Kevin said:

      @ E-M@iLinAtoR, Glad we were able to help and thanks for visiting.

      November 13th, 2008 at 11:08 pm
    3. The Geek Meister said:

      Thanks for this. I’ve been trying to figure out why I’ve only been transferring files at 5mb/s when I have a gigabit network and using cat 6.

      It definitely worked. I’m transferring at 75MB/s now.

      – TheNetSecure –

      August 4th, 2009 at 11:53 am
    4. The Geek Meister said:

      It looks like you don’t even have to reboot. Although I’m sure it helps. I’m transferring files between my computer and server via filezilla ftp.

      August 4th, 2009 at 11:55 am
    5. Kevin said:

      @ The Geek Meister, Glad we were able to help and thanks for visiting.

      August 4th, 2009 at 12:33 pm
    6. Zoltan said:

      Many thanks!

      I waste 4 hours to read forums while i found this. 🙂

      But now everybody happy in the office!



      December 8th, 2009 at 10:10 am
    7. iec said:

      Thanks so much for the insight!

      I don’t think most people realize that this actually can also contribute to issues with downloading/uploading online if your internet is through a network (such as a university network). I’ve seen several forum threads where people had this issue and never had it resolved.

      I’ve dealt with glitchy audio in conjunction with high download speeds for months now. Glad the problem has finally been pinpointed. Hopefully the issue goes away.

      January 25th, 2010 at 2:40 pm
    8. James said:

      O.k. I have a problem… The problem is, when I went to the registry location HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionMultimediaSystemProfile I did not find the NetworkThrottlingIndex. So, do you know how I can make a new entry by any chance ?

      October 22nd, 2010 at 11:37 pm


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