I don't think this is true. Apache with mpm_worker and fastcgi for python/php should perform on a typical dedicated server like nginx till the network is saturated. you also have to consider that .htaccess files are quite cpu intensive because the way apache works they are parsed at every request. put your .htaccess config in the config-file disable unused modules and use mpm worker and I bet the difference is negligible. if you have to count every io operation and you run on small memory nginx may make a difference.

http://nbonvin.wordpress.com/2011/03/14/apache-vs-nginx-vs-v...