[squid-users] Slow / Fast response from squid

I hv set up the BIG squid cache. However, the response times from squid
cache is erratic. Sometimes. slow and sometimes fast.

Expected # of users of these cache: 1000, and currently 2 pilot users.

The specification that I have :-
1xE1 2mbps connection
2GB Physical RAM
2GHz Xeon
RHL 9.0
squid 2.5.1
/var/spool/squid mounted as default ext3 on 1 logical vol of phy vol group
of 4 RAID-0 SCSI disks of 20GB.

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cache_mem 768 MB
cache_dir ufs /var/spool/squid 32000 64 256
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acl QUERY urlpath_regex cgi-bin \? asp
no_cache deny QUERY
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How can i make it have v.fast response time.. just like if i had had used
the connection directly? Any recommendations / suggestions would be
welcomed.
Thanx a lot.
Phil.