Wifi connection drops when using torrent clients

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.

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

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.