PPP slows down the system

[Emil Khatib]

Hi everybody. 
I'm using a 56k connection to access the Internet. I'm using user PPP,
and everytime I dial up, everything works too slow. At least X works
quite bad (and so KDE). When I try "startx", it freezes for a few
seconds and then it starts and takes a long time to load KDE. Also,
the applications in KDE start very slowly (when they start).
Everythings works allright when i get disconnected....
Can anyone give me an idea of what is happening (It isn't the first
time it happens, I've tried in another computer with FreeBSD and it
happens the same)?

I'm using FreeBSD 5.3 amd64.