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I find that whenever my bittorrent client is running, all other communication slows down extremely - this is because of the ACKs taking up all the upload bandwidth.

Can I configure Windows or install a 3rd party application so that the packets of all other applications take precedence over bittorrent's packets?


  1. I'm interested in solutions for Windows 7
  2. Limiting the bandwidth is not good - I want maximum bandwidth when I'm not using the computer, and maximum responsiveness when I am.
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FYI, QoS and priority are two different things. QoS reserves a specific amount of bandwidth for a certain type of traffic and priority allows certain packets to have precedence, but makes no reservations of bandwidth. – MDMarra Aug 10 '09 at 3:56

There is an app that is supposed to do this called CFosSpeed. I've tried it in the past when using an adsl connection and it improved my experience somewhat.

Other than that limiting your upload speed in bittorrent to something like 70-80% of your max upload usually solves the problem as well.

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Quality of Service is built-in in most Windows-versions including an enhanced version in Windows 7. However, the concept is still to reserve bandwidth for prioritized packets - not to adjust bandwidth so I figure that's not what you want to do. Otherwise, here's how you configure it in Vista which would be similar to Windows 7.

uTorrent has an excellent setup guide that needs to be followed to the letter to get a responsive experience overall. Here's a forum thread with some more conservative settings as well.

If your NAT-device ("router") supports at least port-based priority you could use that, otherwise you could either set up a proxy like Squid or install an application that will help you. Most good ones aren't free though. Here's a cheap untested example.

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You need some sort of proxy application. squid will be a good choice. And it's free. There is SafeSquid based on squid with more friendly user interface.

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It should probably be noted that SafeSquid doesn't support Vista yet. – Sasha Chedygov Aug 9 '09 at 20:21
I use squid on Vista with no problems. I believe that SafeSquid is just a web interface to squid settings. – Kirill V. Lyadvinsky Aug 9 '09 at 20:27
Oh really? Nevermind then. The website said it didn't support Vista. – Sasha Chedygov Aug 10 '09 at 0:16

Why not just limit the max bandwidth for downloads in the bittorrent app? Almost all of them have this feature and it is much easier than any other solution you'll get.

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Because I want max bandwidth when I'm not using the computer, but want my traffic prioritized when I am. – ripper234 Aug 10 '09 at 12:04

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