The computer is on a local switch together with an older computer, which in turn communicates well at 25 MB/s with all the rest of the world. At Dell's they propose a hardware support, however not for that model. Nevertheless they support officially CentOS. That's why I asked whether anyone had encoutered the same problem already, and could perhaps provide a solution.

Yours, Peter

I would recommend looking at your network speed/duplex negotiation with your switch. I suspect your switch may be full duplex and your network card half or vice versa. Try forcing your network card to various speed/duplex settings (and your switch if it is a decent managed unit) and re-try your testing. This is the most common cause of network performance issues.

cheers