does filtering increase modem traffic?

Gentlemen, in noffle.conf I have chosen to do
filter bytes>19k action=discard
filter group=gmane.spam.detected action=discard

I am worried that now that I have chosen filtering, what once was just
a simple download now needs to have also a preliminary header check
for each article.

Assuming nothing matches them for a particular modem session, i.e. no
spam on the server today:

Me adding those two lines will now cause the bytes going over my
modem to increase by how much?  These days headers are bigger than
many bodies anyway...

Is all the filtering accomplished in a overview phase that we have to
do for the particular group anyway, thus merely using the CPU more,
not the modem?  Or do we laboriously get each message's header first?

Am I wasting just CPU or also phone money filtering for
gmane.spam.detected even for other servers than gmane?
-- 
http://jidanni.org/ Taiwan(04)25854780



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