This is an obvious performance tip: avoid installing modules that are known to drag down Drupal performance. If you do not need them, do not use them. This espcially relates to any kind of node access related modules. Such modules add extra MySQL database "LEFT JOINS" to match each node table item to the node_access table, to check if the user may access the node.
If you do not need such access rights control, avoid using node access modules. Simply disable and uninstall them. Even if you need to use a node access module, mind the following advice:
In general, you don't want to use more than one node access module on your site. There are many node access modules to choose from: taxonomy access, nodeaccess, simple access, workflow access, etc. We all tend to add lots of modules to our sites and to expect them to play well together, but node access is an area where we need to be extra thoughtful. | http://drupal.org/node/270000
- Keep node queries nice and clean, reduce MySQL load