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Today I am experiencing extremely high ping (200-500 ms instead of usual 20 ms) and low bandwidth (3 Mbps instead of usual 5 Mbps). What can be causing it?

I am using Windows 7, ADSL line, I am aware of having installed following background applications which can be causing some background traffic, each of them running with default settings:

  • Skype
  • email checker (once per 10 minutes)
  • uTorrent
  • web page change notification (once per hour)
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up vote 10 down vote accepted

It's probably your uTorrent, and it's probably the upstream bandwidth.

When the upstream bandwidth is saturated it's much harder for packets to get out of the network, so all your internet seems slower (yes, even download speeds).

Try limiting the upstream bandwidth on uTorrent to no more than 80% of your actual upstream bandwidth.

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I can confirm it was uTorrent (actually I already knew the answer and, but as it was not very easy to find, I have posted the question here, so that it is easier for those who come after me). I am quite surprised the specialized network tool like Torrent does not handle this on its own - this makes it still limited to computer enthusiasts (it is not difficult to handle this automatically). – Suma Mar 21 '11 at 13:36
Limiting the upload reduced the problem, but when uploading, the ping is still higher that e.g. when download large files from web. I think following article provides a possible explanation:… – Suma Mar 21 '11 at 13:52
@Suma I actually put up an explanation of why uploading causes high latency in one of my answers:… – Mokubai Mar 21 '11 at 14:03
A large percentage of calls to ISPs relating to slow speeds turn out to be over-utilization. For ADSL lines, it is commonly upload speed that kills it. Synchronous connections are less prone to this problem, but in general, misconfigured torrenting programs will kill any circuit they are run on. – MaQleod Mar 21 '11 at 14:12

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