synaptics touchpad

I just installed FreeBSD 5.3-Beta5 on my Dell Inspiron 7500, which has a 
synaptics touchpad.  I am finding the touchpad to be somewhat 
unresponsive, particularly under XFree86-4.3.  (I would use Xorg, but 
neither Xorg or XFree86-4.4 work with my video card.)

In the end I went into the source code sys/isa/psm.c, and simply 
commented out the synaptics code, so that FreeBSD thinks that it is a 
generic mouse.  Now it works very much better.

Why would the synaptics code be so unresponsive?  Do I need to use Xorg, 
or is it some other issue?

Stephen