pf and keep/modulate state on 6.2

[J.D. Bronson]

I was noticing sporadic FTP transfers DOWN to my fbsd 6.2 machine 
over my DSL line...it would go/pause/go/pause - just a bit, but 
overall slowed the transfers down quite a bit.

I looked at my pf.conf file and changed MODULATE state to KEEP state
in all places and my issues went away....fast clean consistent downloads.

If I changed it back...the issues came back.

is this expected behavior? - the machine is a p4-3.06 with 1GB ram 
and hardly doing anything but PPPoE and pf with NAT.

Anyone have any comments they could share?

-JD