>> With HipHop we've reduced the CPU usage on our Web servers on average by about fifty percent, depending on the page
>> PHP is a scripting language with dynamic, weak typing. <...> Whenever possible our generated code uses static binding for functions and variables. We also use type inference to pick the most specific type possible for our variables and thus save memory.
Несколько цитат из: developers.facebook.com/blog/post/358/
>> With HipHop we've reduced the CPU usage on our Web servers on average by about fifty percent, depending on the page
>> PHP is a scripting language with dynamic, weak typing. <...> Whenever possible our generated code uses static binding for functions and variables. We also use type inference to pick the most specific type possible for our variables and thus save memory.