I encounter a strange issue with my web (wireless) connection on my laptop (Ubuntu 11.10) I'm able to have 540kbps (down) on all computers in my house (including laptop at the same distance from the box) except me. When i do a speed connection test, i can have this optimal speed immediately after booting. As i surf on the net, watching videos, download things, etc... it becomes slower progressively until 100-110 kbps and the speed remain the same until i reboot.

I tried to figure out if a process consume bandwith in background with nethogs but i found nothing suspicious. Any ideas ?

Thanks in advance for your help !!