In this quick post to her blog, Lorna Mitchell shares an interesting bit of benchmarking she did between PHP versions 5.3 and 5.4, finding 5.4 twice as fast as it's previous version sibling.

So recently I was working on some benchmarks for different versions of PHP, because I heard that PHP 5.4 is "faster" and since I'm a data geek I want to know how much faster! Now, PHP 5.4 is, in general, faster than PHP 5.3 but not twice as fast* unless you pick a use case which has been particularly optimised. My first attempt at benchmarking the two versions produced this. This was a surprise to me; was PHP 5.4 really so much faster??

Her benchmark was a pretty simple one - looping and creating a new object, evaluating the timing of how long it took to execute. A commentor also points to some more official benchmarks that were done and posted to the php.internals mailing list.