Once again I'm being lazy and in hurry, so it's a copy and paste.
There are two customizations explained in this article. They are:
1. Speeding up Firefox during loading by putting it in XP's prefetches list.
2. Speeding up the maximizing of Firefox
1. Speeding up Firefox on Windows XP
You can speed up the loading of Firefox on Windows XP by adding it to the programs that XP prefetches.
To do this:
1. Right-click the Start Menu item for Firefox, or any icon you use to start Firefox, and open the Properties dialog box.
2. Add a space plus /Prefetch:1 to the command line and click OK. The resulting line might look as follows:
"C:\Program Files\Mozilla Firefox\ firefox.exe” /Prefetch:1
2. Speeding up the maximizing of Firefox
1. Use about:config to create a new, Boolean value.
2. Type or paste the following string into the dialog box that appears: config.trim_on_minimize
3. Click OK to close the dialog box.
4. Change the value from true to false
5. Restart Firefox.
Virtual Hard Drive takes a portion of your system memory (RAM) and uses it like a hard disk drive, dramatically increasing read and write times. Applications perform up to 340 time faster, making Virtual Hard Drive the software of choice for anyone looking to reduce the load and response time of calculation-intensive applications.
Creating a RAM disk on you hard disk, Moving Firefox’s cache directory there.
Resources
Moving your Firefox’s Cache Files, Tweaking Firefox Tips&Tricks Disclaimer
Disclaimer applies.