<?php

$loops = 10000;
$start = microtime(true);

$arr0 = $arr1 = [];
for ($i = 0; $i < $loops; $i++) {
	$arr0[$i] = array_fill(0, $i, md5(mt_rand($i, PHP_INT_MAX)));
	$arr1[$i] = $arr0[$i];
}

$total = microtime(true) - $start;
$avg = $total / $loops;

echo "Average: " . $avg . "s\n";