It’s a fact that script based languages and frameworks slow you down. PHP and its huge amount of frameworks is no exception to that rule. Until you realize that it is used on the busiest site out there – Facebook.
Scripted languages typically are embraced as they have advantages in being simple to learn, code, and debug while counterbalanced with a definite sacrificing of speed. On the other side of the spectrum, compiled languages usually have a steeper learning curve and are much more strict; counter balanced with the clear fact that they are considerably faster and better optimized for handling memory. Facebook seems to have found a balance between both worlds with HipHop for PHP.
Facebook developers write lots of their core services in other languages, and then PHP is used as the glue that queries those services and builds the actual pages itself. Still, they have found that that really isn’t fast enough for what they want, so they went and wrote their own compiler, or rather an optimizer, called HipHop, which compiles PHP down to C++ which can then be compiled by G++.
You can download HipHop from here: http://github.com/facebook/hiphop-php
Learn more here: http://developers.facebook.com/blog/post/358 and here: http://therumpus.net/2010/01/conversations-about-the-internet-5-anonymous-facebook-employee/4/
If you’re interested in using/trying some PHP frameworks you can start by looking at: