Possible Duplicate: How do you do Load Testing and Capacity Planning for Web Sites I'm installing a social network using Zend Framework & MySql, with lots of plugins & queries. I want Webserver & Sql server on one box. I'm trying to choose between two machines (on hetzner.de): A) intel i7-2600 3.4 GHz 16 GB DDR3 RAM B) intel i7-920 2.6 GHz 24 GB DDR3 RAM B has 50% more RAM but 30% slower clock speed. Q is: is it obvious where the bottleneck will be? Would I ever need 24GB of RAM, even with lots of concurrent users?