Etienne Kneuss has posted about a new part of the Standard PHP Library that creates arrays that are up to thirty percent faster than normal methods - SplFastArray.
Antony got the idea to implement a C-like array wrapper in SPL: SplFastArray. The main advantage of that class is performance, it's indeed faster than PHP arrays. How so? No free lunch: The speedup comes from the fact that non-numeric indexes are not allowed and that the array is of fixed size.
The code sample shows the setting of the size for the array (and changing it) with a var_dump of the output result. This method is always faster than normal arrays, it just varies how much from system to system (anywhere from ten to thirty percent).