Compare Apache/mod_php and nginx/php-fpm
blog.a2o.si
blog.a2o.si
The results were definitely not what I expected. Both servers were able to crunch roughly the same number of requests per second. Nginx won by 20% in some situations, Apache won in a few others, but the margin was never really that significant.
However, it's important to note that there were huge differences in CPU load while running the benchmarks. Running "ab -c50 -n100000" would bring load to 30 with Apache, but only 0.7 with Nginx! Apache also used a lot more ram.
I assume there must be some other bottleneck (disk access?) keeping Nginx from utilizing more of the CPU, hence the fairly close results.