Alwyn Botha has produced a very comprehensive comparison of blog site speeds where WordPress is compared with 8 other content management systems.
You can check out the WordPress, Drupal, Joomla, Moveable Type… comparisons at pageloadtime.com. It’s a shame that Habari wasn’t included, but at the moment it probably wouldn’t have been a fair comparison.
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it seems his site is down? I also wrote a small article about his site: http://pacura.ru/blog/site-server-optimization/
btw. to be honest, I think most of his tremendous work is useless. make sure you also read all the comments on his articles to get a broader view on his work…