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uTorrent consuming 100% CPU and slow start


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Today I updated to the 2.0 version (used 1.8.5) and noticed that new version is very slowly to start (took about 3 minutes, tested and restarted many times). And noticed that my CPU Usage is fixed in 100% when utorrent is open.

I'm running it in a "green" pc (VIA nano 7, 1.5ghz, 1gb ram) with Windows 7 Ultimate 32bits (without aero) and no AV, just Windows Firewall.

Any ideas?

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@MagusBR: From what I can tell, it looks like you have enabled "allow_same_ip" (which is disabled by default), and then you have a lot of torrents with a lot of peers stored in the resume.dat file. When all these peers are added, we make sure we don't add duplicates. This test is cheap when allow_same_ip is off, because the peer list is hashed on the IP. When allow_same_ip is true however, we look for duplicates by comparing peer-id, and IP+port. This is expensive, because we do a linear scan of all peers in the list.

Unless the data in this dump is corrupt (sometimes it is), it looks like you were adding the 29471st peer when you made the dump. This is a very large number of peers, and it would take a long time to add them all.

You might want to switch allow_same_ip back to false.

If you want confirmation that this is actually the problem, open your resume.dat and search for the string "peers6" and look at the number immediately following. This number tells you how many IPv6 peers you have in there. There are multiple entries of "peers6", at least one of them should have a large number for my theory to be confirmed.

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Thanks arvid and Firon, i just switch "allow_same_ip" back to false and the problem gone ;)

About the linear scan, is the list sorted first? :P

And yesterday was the release of first Lost ep from season 6, and was when I updated the µTorrent to 2.0 ^^'

Thanks again,


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