This is a quick way to speed up drupal on a localhost.

1. Disable ZoneAlarm

ZoneAlarm seems to present big issues for Drupal and makes it run at a crawl. Disable (or even completely uninstall ZoneAlarm) if you want Drupal to run faster.

2. Check PHP.INI

Find the php.ini on your server. In wamp you click on the toolbar icon -> select PHP -> select php.ini

Push ctrl+ f and find "realpath_cache_size" . Remove the semi-colon at the beginning of the line and make it =16M instead of 16k .

3. Check Windows Hosts File

(this option has been tested for vista and win7)
"add a sharp character ('#') as the first character of the line containing: ::1 localhost in your c:\Windows\System32\drivers\etc\hosts

More detail

What this smallish change does is remove IPv6 localhost resolution from the hosts file. It is likely to cause other problematic situations if you do any IPv6 work, of course, and then you'll probably want to dig deeper into your network and/or Apache config."

taken verbatim from
http://blog.riff.org/2008_11_22_speeding_up_drupal_on_vista_with_wampserver

Also consider disabling update status, unless you really need it. This stops drupal from checking for updates all the time and helps a bit if you are on a connected box.

4. Try a different server stack

Some users have reported performance improvements when using ZendServer (the free community edition) rather than XAMPP, WAMP, MAMP or EasyPHP. ZendServer includes several modules that perform opcode caching which seem to make a significant difference.
http://www.zend.com/en/products/server-ce/

Another significant option is the Acquia Drupal Stack: http://network.acquia.com/downloads

Update For Firefox

Enter in the URL field of Firefox this:
about:config

Then hit enter - Note:Firefox will give you a warning message saying this This must void your warranty!

Just ignore that and click the button saying I'll be careful, I promise! after hitting the button, Firefox will show you a Filter field and all it's configuration.Don't change anything in the configuration instead search for ipv6 in the Filter.

Firefox will return a value of network.dns.disableIPv6 with status of default and a type of boolean and a value of false

network.dns.disableIPv6 default boolean false

just double click that configuration to change the value from false to true and it will also change it's status to user set

network.dns.disableIPv6 user set boolean true

just close that tab after you set the configuration.
restart Firefox and done.

taken from http://drupal.org/node/348202