“PHP has matured into a powerful language that’s easy to learn
and is supported on many platforms. However, flexibility and ease
of use come at a price: system performance. PHP, like all
interpreted languages, must be converted to code native to the host
system. In the compiled languages, the compiler does this once
before deployment, of course, (a pain when incrementally upgrading
a live project). Interpretation can impact performance
considerably, especially on a smaller system or a heavily loaded
one, because it takes time to perform. PHP is by no means slow, but
it’s still slower than code that’s compiled beforehand and runs
natively on a system (though Zend Technologies, employer of PHP
inventors, developers, and administrators claim to have increased
the PHP4 interpreter’s speed 20 to 100 percent over PHP 3).”
“Zend Technologies totally rewrote the PHP 4 interpreter, called
the Zend Engine, following a new set of design philosophies that
affected many features including modularity and extensibility. As I
mentioned before, these changes made the interpreter much faster
when faced with complex scripts. The Zend Engine’s modularity will
also allow the Zend folks to introduce several products later this
year that will further increase PHP’s performance. One available
now is the Zend Optimizer.”