Speedup Your Magento Site
1. first we need to update .htaccess file on root. this code below activate Gzip compression.
## http://developer.yahoo.com/performance/rules.html#gzip
# Insert filter
SetOutputFilter DEFLATE
# Netscape 4.x has some problems_
BrowserMatch ^Mozilla/4 gzip-only-text/html
# Netscape 4.06-4.08 have some more problems
BrowserMatch ^Mozilla/4.0[678] no-gzip
# MSIE masquerades as Netscape, but it is fine
BrowserMatch bMSIE !no-gzip !gzip-only-text/html
# Don’t compress images
SetEnvIfNoCase Request_URI .(?:gif|jpe?g|png)$ no-gzip dont-vary
# Make sure proxies don’t deliver the wrong content
Header append Vary User-Agent env=!dont-vary
# enable resulting html compression
php_flag zlib.output_compression on
2. secoundly we need to save all products and category as ‘FLAT RESOURCE’
a. go to system->configration->catalog->frontend
b. Use Flat Catalog Category, Use Flat Catalog Product you will see these 2 option at the end, Select Both to Yes.
c. reindex all data from Index Management.