There are many modules enabled by default in apache config which are not required to run a typical magento installation. Disabling these modules can help optimize performance for Magento. There are around 26 modules in this list, so you can imagine how much positive difference it can create on server performance. Here is the list of apache modules which we were able to disable safely. This list is published just to give you idea, so be careful and consider your specific needs before disabling these. Here is the list

  1. proxy
  2. proxy_ajp
  3. proxy_balancer
  4. proxy_connect
  5. proxy_ftp
  6. proxy_http
  7. bw (bandwidth usage)
  8. cache (disk and memory cache)
  9. disk_cache (disk and memory cache)
  10. speling (tries to find misspel docs)
  11. status (to get apache status)
  12. substitute (find replace in output)
  13. suexec (allows to run cgi under some user and group)
  14. userdir (point user real directory)
  15. usertrack (click stream recording)
  16. vhost_alias (Dynamic vhosts)
  17. cgi (cgi support)
  18. version (allows to use IfVersion in htaccess)
  19. ext_filter (extends filters)
  20. authn_anon (authenticate anonymous)
  21. authn_dbm
  22. authz_ldap
  23. authz_dbm
  24. info
  25. authz_owner
  26. include
  27. logio
  28. authn_alias
  29. authn_default
  30. ldap
  31. authz_groupfile
  32. authz_default
  33. suexec

Please do it on your own risk and test site after disabling each apache module one by one. You can disable modules by using hosting control panel or by editing apache config file. Add comments if you find it useful.