As described in chapter 4, while you shouldn't hesitate to install modules you need, you should also disable modules that you aren't using in order to speed up your site's performance.

There are a few core Drupal modules that you can probably turn off:

• Color (if your theme doesn't use the color picker feature; see Chapter 18 for more on themes)
• Comment (if your site doesn't use comments)
• Statistics (especially if you're logging access statistics using another service, like Google Analytics)

Of these, only Statistics is likely to lead to much of a performance gain. Statistics writes to the database every time someone accesses a page, which slows down load times. 

If you're working with a sysadmin, you might be able to turn off the Database logging module (dblog), which writes log messages to the database. The upside of using Database logging is that you can access the log through Drupal's interface, at Reports > Recent log messages (/admin/reports/dblog). However, writing these messages to the database slows down site performance slightly. If you disable Database logging and enable the Syslog module, you won't be able to easily monitor the log yourself, but your sysadmin can keep an eye on it.