consuming a lot of memory

[3cwired_com]

I am using debian lenny with the perfect setup and this is a sample list from top:

mysql	152304 kB	/usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file ...
2462	clamav	98948 kB	/usr/sbin/clamd
7210	www-data	91252 kB	/usr/sbin/apache2 -k start
7329	www-data	86208 kB	/usr/sbin/apache2 -k start
7293	www-data	85724 kB	/usr/sbin/apache2 -k start
7213	www-data	83936 kB	/usr/sbin/apache2 -k start
7215	www-data	83932 kB	/usr/sbin/apache2 -k start
7307	www-data	83404 kB	/usr/sbin/apache2 -k start
7214	www-data	83148 kB	/usr/sbin/apache2 -k start
7257	www-data	83148 kB	/usr/sbin/apache2 -k start
7305	www-data	82444 kB	/usr/sbin/apache2 -k start
7212	www-data	82344 kB	/usr/sbin/apache2 -k start
7306	www-data	82184 kB	/usr/sbin/apache2 -k start
7331	www-data	79060 kB	/usr/sbin/apache2 -k start
7256	www-data	78760 kB	/usr/sbin/apache2 -k start
7261	www-data	78760 kB	/usr/sbin/apache2 -k start
7330	www-data	78760 kB	/usr/sbin/apache2 -k start
7373	www-data	78740 kB	/usr/sbin/apache2 -k start
7278	www-data	78628 kB	/usr/sbin/apache2 -k start
7372	www-data	78328 kB	/usr/sbin/apache2 -k start
3312	root	78196 kB	/usr/sbin/apache2 -k start
7208	www-data	67260 kB	/usr/sbin/apache2 -k start
28172	amavis	57696 kB	amavisd (ch18-avail)
28715	amavis	57288 kB	amavisd (ch15-avail)
1394	amavis	54420 kB	amavisd (master)
1923	root	47520 kB	/usr/sbin/lwresd
1798	root	29040 kB	/usr/sbin/spamd --create-prefs --max-children 5 --helper-home-dir -d --pidfile=/ ...
1806	root	29040 kB	spamd child
1807	root	29040 kB	spamd child
1835	root	28428 kB	/usr/sbin/rsyslogd -c3
29115	root	23980 kB	/usr/bin/python /usr/bin/fail2ban-server -b -s /var/run/fail2ban/fail2ban.sock
7190	root	14036 kB	/usr/share/webmin/proc/index_size.cgi
3007	root	12508 kB	/usr/sbin/smbd -D
3073	root	12508 kB	/usr/sbin/smbd -D
3372	root	12440 kB	/usr/bin/perl /usr/share/webmin/miniserv.pl /etc/webmin/miniserv.conf
7275	postfix	11744 kB	smtpd -n smtp -t inet -u -c -o stress
7353	postfix	11744 kB	smtpd -n smtp -t inet -u -c -o stress
3116	root	9116 kB	/usr/sbin/winbindd
3129	root	9116 kB	/usr/sbin/winbindd
3074	root	8360 kB	/usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5
3079	root	8360 kB	/usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5
3080	root	8360 kB	/usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5
3081	root	8360 kB	/usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5
3082	root	8360 kB	/usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5
20610	root	8160 kB	sshd: root@pts/0
7403	postfix	8116 kB	trivial-rewrite -n rewrite -t unix -u -c
7404	postfix	8104 kB	proxymap -t unix -u
18826	postfix	8020 kB	qmgr -l -t fifo -u
7140	web2	7796 kB

I am not sure why all of these processes takes up so much ram if not needed. Is there anyway to tweak and tune these processes so that they dont take up much more memory. Thanks.