Problems with eaccelerator
http://www.drupalarchitect.com/drupal-segmentation-fault-using-eaccelerator-or-x-cache
http://www.jeffbeeman.com/node/101
http://www.freshblurbs.com/beware-eaccelerator-and-php-zlib-compression
http://eaccelerator.net/ticket/155
http://drupal.org/node/130106
http://www.jeffbeeman.com/node/101
Stupid problems:
http://drupal.org/node/143348#comment-231152
A solution???
http://www.mojahmedia.net/eaccelerator-suexec-zend-white-screens-death-drupal.html
drupal APC Installation howto
http://www.cpanelconfig.com/optimize-a-cpanel-server/how-to-install-apc-php-cache/
Drupal high-performance discussion group
http://groups.drupal.org/high-performance
Other interesting articles:
http://www.scribd.com/doc/3991611/Drupal-Performance-and-Scalability