Pre vs Post Increment in PHP

Earlier on I was browsing Google Code, and I chanced upon JSpeed - a javascript optimizer. I saw that they actually change post increments to pre-increments. I wondered why and thought I could ask this on Stack Overflow.

One theory came up to be "preincrement (++i) adds one to the value of i, then returns i; in contrast, i++ returns i then adds one to it, which in theory results in the creation of a temporary variable storing the value of i before the increment operation was applied". -- http://physical-thought.blogspot.com/2008/11/pre-vs-post-increment-speed-test.html

So I thought, what about PHP?

I went on to test it on PHP with a FOR loop and I have the following code:
<?php

$time_start = microtime_float();

for($i = 0; $i<10000000;$i++){

}

$time_end = microtime_float();
$loadedin = (float)($time_end - $time_start);
echo $loadedin.' s
';

$time_start = microtime_float();

for($i = 0; $i<10000000;++$i){

}

$time_end = microtime_float();
$loadedin = (float)($time_end - $time_start);
echo $loadedin.' s
';

function microtime_float(){
list($usec, $sec) = explode(" ", microtime());
return ((float)$usec + (float)$sec);
}


?>

Amazingly, pre-increment is much faster than post-increment in PHP. Look at the results:

	Pre-inc (seconds)	Post-inc (seconds)
Mean	0.68695	0.74147
Min	0.685925960541	0.740597963333
Max	0.68816781044	0.743010044098

Thus I conclude that pre-increment is useful in for loops than post-increment. It is much faster through the iterations.