Ralink rt2400 weak

I have recently tried openSUSE 11.3 on another pc which use a pci wireless card. The system installed the rt2400pci driver and so wlan0 comes up.
The problem is the poor signal that shows not more than 10% where in windows is about the 40%.
This seems to be driver problems isn’t it? Is there someone who have heard something like this with ralink wireless cards before? Any idea to solve this?

By the way this pc has internet thanks to a homemade can wifi boost connected to the pci plug.

PS: No, I can’t move the router closer :stuck_out_tongue: