X sluggish after upgrade to 4.1

[Jesper Holmberg <jesper.holmberg@enst-bretagne.fr>]

After a short vacation, I yesterday did an upgrade of my Testing system,
bringing me the xfree86 4.1. Now, my X seems quite sluggish, especially
noticeable when scrolling in a web browser (I've tried several).

I first suspected this could have something to do with the frame buffer,
but I have tried both:

Section "Device"
        Identifier      "Generic Video Card"
        Driver          "neomagic"
        Option          "UseFBDev"              "false"
EndSection

and

Section "Device"
        Identifier      "Generic Video Card"
        Driver          "neomagic"
        Option          "UseFBDev"              "true"
EndSection

with no noticeable difference.

I use an Dell Latitude laptop, with a Neomagic video card. What should I
do?

TIA,

Jesper