We are managing a heavy traffic php site (driven with vbulletin). To get less load I use the cache-proxy varnish. Works very well - with varnish the load was reduced by 50%.

But now I am thinking about which webserver to use behind varnish. 90% requests getting to the webserver are php-requests. So is there a difference between apache/mpm-prefork with mod_php and nginx/php-fpm? Is apache perhaps better, because it doesn't have the tcp overhead?

Thanks for reply - benchmarks would be great!

macindy