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I've read the topics I could find which are similar to this, but I've got no help reading them. So this is my situation:

Whenever I start downloading a torrent, my wifi connection drops(as in no packets in or out, and pretty soon getting the limited connection icon). I don't know when this started, because I haven't downloaded torrents for some time, but I remember very well that with this same setup I used to be able to download torrents without problems. The issue is not happening on wired connection. I got other devices connected to the same network and they have no problem whatsoever. Not even while my laptop is getting disconnected. Left ping running on another system connected to the same router while my laptop was getting disconnected: not even a packet lost.

The wireless router has open-wrt set up and works very well. Nothing gets written in the System log or the kernel log. At first I suspected the driver, so I reinstalled the stock driver which comes with windows (made by Microsoft): same issue. Went back to the manufacturer driver (Broadcom) and then fiddled with the various settings it has: same issue. Then I suspected that the number of concurrent connections would bottleneck somewhere, so I limited the torrent client drastically to about 10 connections globally (which is stupid, btw): same issue.

The I suspected the torrent client, so I tried another one: same issue. I tried it the firewall both on and off: same issue. I then suspected windows itself, so I booted a Ubuntu VM (was worth a try, even though the traffic gets NATed through the host OS): same issue. I began suspecting the WiFi adapter being flawed. So to be sure, I booted a live Ubuntu off a USB stick and then came the real shocker: WORKED PERFECTLY reaching 6-7 MB/s sustained with peaks of 9 MB/s. And now I have no clue where the real problem is!!! Not really willing to reinstall the OS.

Here are the specs of my system:

- Dell Inspiron N5010
- stock wifi adapter changed with a Broadcom one (don't know exact model, it's the same one from HP Pavilion dv4-1001ax Entertainment Notebook PC )
- Windows 8 Professional x64
- torrent clients tried: utorrent and tixati
- security suite: Bitdefender Internet Security 2013
- wireless router: Tp-link tl-wr841nd with open-wrt

Hope you guys can give me a helping hand. I don't know what else to try anymore and I hate the idea of having to dualboot just so I could download torrents.

Edit: I want to add that after the connection drops, it is immediately available for reconnecting. After I reconnect, the torrent client barely reaches a few KB/s and then drops again. And so on until I stop the torrent or exit the client. If I download in a browser some large file, it downloads with high speeds (8-9 MB/s) without any problem. The rest of web browsing, chatting, etc. work very well, without interrupts.

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what are the packets sizes? check if your wifi has a limit on cache size. –  Buscar웃 Apr 24 '13 at 22:52
    
Don't know how to check for the packets' sizes or the cache limit. Could you point me in the right direction?The fragmentation threshold is 2346. Should I set it to less? –  Mihai Apr 24 '13 at 23:12
1  
The ISP has nothing to do with it. As I mentioned in the post, on Ubuntu it works flawlessly with the same system, same router, same Internet connection. –  Mihai Apr 24 '13 at 23:13
    
@Buscar웃: What could his ISP do that would cause his WiFi connection to drop? –  David Schwartz Apr 24 '13 at 23:29

3 Answers 3

Try different WiFi drivers. Most probably the problem in drivers. Try to search errata for your wireless adapter.

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Please be a bit more precise in your answer. Don't just point out where the problem might be, try to give detailed instructions on how to solve it if you can. –  Simon Apr 25 '13 at 7:54
    
I have the latest drivers for my device (both from Broadcom and Microsoft). Do you mean I should downgrade? –  Mihai Apr 25 '13 at 22:46
    
@Mihai If you have number of driver versions you can try each version. As I understood your problem is easily reproducible. –  Nikolai Apr 30 '13 at 12:30
    
You can try to open support issue in Microsoft or driver manufacturer. –  Nikolai Apr 30 '13 at 12:30
    
I was away on vacation. Will try finding other driver versions and see what I can get out of it. –  Mihai May 4 '13 at 19:17

With utorrent have you tried adjusting the Maximum upload rate and Maximum download rate under the Bandwidth Preferences. If you are getting torrents over Wifi the link may be becoming saturated. A good starting point would be to calculate the upload/download speed of your WiFi connection then adjust the settings above to about 80%.

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It is not a matter of bandwidth. Browser downloads run fine with high speeds and so do torrents in Ubuntu. –  Mihai Apr 25 '13 at 22:45

MTU = also known as the minimum transmission unit is controlled at the system and router level and can affect the stability of your connection.

Assuming your data you are transferring is regularly of a certain size the MTU may cause a bit of a lag in what gets transferred.

Changing the MTU, whether by editing the router control panel or going to the command line can frequently solve dropped connection issues.

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Changing it in what direction? Higher? Lower? It is 1500 at this moment. I still find it irrelevant, considering that torrents in Ubuntu work fine. But I shall try as soon as someone tells me a good value to try. –  Mihai Apr 25 '13 at 22:49

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