please check my squid config

[ahuray_mazdaa]

please check my squid config and tell me your suggestion for improve performance
20gig hdd
756ram

shutdown_lifetime 60 seconds
icp_port 0
http_port 3128
hierarchy_stoplist cgi-bin ?
acl QUERY urlpath_regex cgi-bin \?
no_cache deny QUERY
visible_hostname Cache_Proxy
cache_effective_user squid
cache_effective_group squid

pid_filename /var/run/squid.pid

cache_access_log /var/log/squid/access.log
cache_log /dev/null
cache_store_log /dev/null
logfile_rotate 3
log_mime_hdrs off
forwarded_for off
cache_replacement_policy lru
memory_replacement_policy lru
cache_dir diskd /cache 2000 16 256 Q1=72 Q2=64
cache_mgr administrator@xxxx.net 
log_fqdn off
cache_swap_low 90
cache_swap_high 95
acl nimda1 urlpath_regex -i \.elm$
acl nimda2 urlpath_regex -i root.exe
acl nimda3 urlpath_regex -i cmd.exe
acl nimda4 urlpath_regex -i ^http://.*www/
acl nimda5 urlpath_regex -i readme.exe
acl nimda6 urlpath_regex -i default.id
acl nimda7 urlpath_regex -i :25
acl all src 0.0.0.0/0.0.0.0
acl manager proto cache_object
acl localhost src 127.0.0.1/255.255.255.255
acl SSL_ports port 443 563
acl Safe_ports port 80 # http
acl Safe_ports port 21 # ftp
acl Safe_ports port 443 563 # https, snews
acl Safe_ports port 70 # gopher
acl Safe_ports port 210 # wais
acl Safe_ports port 1025-65535 # unregistered ports
acl Safe_ports port 280 # http-mgmt
acl Safe_ports port 488 # gss-http
acl Safe_ports port 591 # filemaker
acl Safe_ports port 777 # multiling http
acl CONNECT method CONNECT
acl ncsa_users proxy_auth REQUIRED
acl VALID-NETWORK src xxxxxx
acl UNVALID-NETWORK src 172.16.100.0/24
acl Movies rep_mime_type video/mpeg
acl MP3s rep_mime_type audio/mpeg
 
http_access allow VALID-NETWORK
http_access allow UNVALID-NETWORK
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow localhost
http_access deny nimda1
http_access deny nimda2
http_access deny nimda3
http_access deny nimda4
http_access deny nimda5
http_access deny nimda6
http_access deny nimda7
http_access deny all
http_reply_access deny Movies
http_reply_access deny MP3s
http_reply_access allow all
 

httpd_accel_port 80
httpd_accel_host virtual
httpd_accel_with_proxy off
httpd_accel_uses_host_header on
ie_refresh on
#snmp 
snmp_port 3401
acl snmppublic snmp_community xxxx
acl local src 127.0.0.1
snmp_access allow snmppublic local
snmp_access deny all
cache_mem 64 MB # 8 MB
maximum_object_size 1 MB # 4096 KB
maximum_object_size_in_memory 32 KB # 8 KB
dns_nameservers xxxxxxx

request_header_max_size 35 KB # 10 KB
request_timeout 120 second # 5 min

refresh_pattern windowsupdate.com/.*\.(cab|exe|psk) 4320 100% 43200 reload-into-ims
refresh_pattern download.microsoft.com/.*\.(cab|exe|psf) 4320 100% 43200 reload-into-ims
refresh_pattern au.download.windowsupdate.com/.*\.(cab|exe|psf) 4320 100% 43200 reload-into-ims

quick_abort_min 32 KB
quick_abort_max 32 KB
quick_abort_pct 95
negative_ttl 3 minutes
positive_dns_ttl 6 hours
pipeline_prefetch on

[ahuray_mazdaa]

and refresh pattern (each post limit to 1000)

refresh_pattern -i ^ftp: 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.jpg$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.html$ 57600 50 60000 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.class$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.zip$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.jpeg$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.mid$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.shtml$ 57600 50 60000 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.exe$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.thm$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.wav$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.txt$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.cab$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.au$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.mov$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.xbm$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.ram$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.avi$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.chtml$ 57600 50 60000 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.thb$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.dcr$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.bmp$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.phtml$ 57600 50 60000 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.mpg$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.pdf$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.art$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.swf$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.mp3$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.ra$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.spl$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.viv$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.doc$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.gz$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.Z$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.tgz$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.tar$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.vrm$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.vrml$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.aif$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.aifc$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.aiff$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.arj$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.c$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.cpt$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.dir$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.dxr$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.hqx$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.jpe$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.lha$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.lzh$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.midi$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.movie$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.mp2$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.mpe$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.mpeg$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.mpga$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.pl$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.ppt$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.ps$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.qt$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.qtm$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.ras$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.sea$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.sit$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.tif$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.tiff$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.asp$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.aspx$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.php$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.js$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.jsp$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.perl$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.cgi$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.fla$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.xml$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.xhtml$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.sxml$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.ocx$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.java$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.css$ 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \. 57600 90 86400 override-expire override-lastmod reload-into-ims
refresh_pattern -i \.htmx 57600 90 86400 override-expire override-lastmod reload-into-ims