If your video card isn't supported by XFree86 4.x, and lots of old
chips aren't...486 machines should just go to that great computer
grave yard after all...

Anyway, RedHat/Fedora/Whater is detecting your chipset, and most
likely using XFree86 v3.x instead of v4.x, thus the better
performance.

It looks like Debian has dropped support for XFree86 v3 in
Testing/Unstable, but you could add in stable source lines and fetch
the old version of your XServer.

Debian is trying to tell you something: Get rid of that old laptop. :)

-- 
Andrew S. Zbikowski | http://andy.zibnet.us
 A password is like your underwear; Change it
 frequently, don't share it with others, and
     don't ask to borrow someone else's.