b2evolution comes with an
.htaccess file destined to optimize the way b2evolution is handled by your webseerver (if you are using Apache). In some circumstances, that file may not be automatically activated at setup. Please se the man page about Tricky Stuff for more information.
For further optimization, please review the manual page about Performance optimization. Depending on your current configuration and on what your web hosting company allows you to do, you may increase the speed of b2evolution by up to a factor of 10!