Strange behavior of Ethernet connection

I never had such a problem before bot now I got it. Maybe someone has a solution… So, here it is.

I started to setup openSUSE 11.1 x86 onto my laptop Toshiba M70. The installation from DVD media went fine. Next I updated the installed system to what it recommended to and switched to repositories on the internet instead of using DVD as a primary media. I did it usually. As at home I have a pretty fast connection (12 Mbits/s). So I chose a pretty much packages to install (about 20 Gb) and started to wait. By the time as 16 hours passed I got only 75% downloaded and installed. And what I noticed was the downloading speed was only 5-7 kBytes/sec! I launched browser. While it was starting up I noticed that the download speed increased and after the browser was up and running the download speed fell down again. Finally experimenting I found out that my download speed is in direct connection with whether the HDD has some activity or not! I also noticed that while installation YAST set Network Manager instead of IfUp. All my previous experience was with IfUp.

So, here is the summary:

  1. Internet connection is done through Ethernet card;
  2. Network is managed through Network Manager;
  3. The problem is that while HDD has no activity the internet connection speed falls down to 5-7 kBytes/s, and when there is any activity on HDD (for example, any file copying in progress) the internet connection speed is at maximum (12 MBytes/s).