This gist is to show that in php objects are much fater than arrays when you need to modify the passed object/array's contents.

php-7.2-objects-faster-than-arrays.php

<?php
/**
 *  Test on PHP 7.2 and PHP 5.4
 *
 ** This gist is to show that in php7.2 objects are much fater than arrays.
 **
 ** 1: We create an object with 10 million properties
 **      We pass it to a function 99999 times and modify a property
 **      We pass it to a function by reference 99999 times and modify a parameter
 **
 ** 2: We create an array with 10 million elements
 **      We pass it to a function 99 (As it's just to slow to wait) times and modify a property
 **      We pass it to a function by reference 99999 times and modify a parameter
 **
 ** Results:
 * 999999 x Object passing time:           0.155613
 * 999999 x Object pass by reference time: 0.154327
 * 99     x array passing time:            5.640978 (for just 99!) 
 * 999999 x array pass by reference time:  0.149588
 * 
 * As you can see array's are ever so just marginly faster, but not enough to worry about in real life
 * If you should ever pass an array and modify the contents then this is a HUGE bottleneck in your system
 * 
 * Conclusion: Avoid modifying arrays passed to functions, or just use objects.
 */
for ($i=0;$i<=999999;$i++) {
    $data['a'.$i] = $i+100000;
}
$data = (object)$data;

$time = -microtime(true);
for ($i=0;$i<=99999;$i++) {
    oslow($data);
}
$time += microtime(true);
echo "Object time: \n", sprintf('%f', $time), PHP_EOL;

$time = -microtime(true);
for ($i=0;$i<=99999;$i++) {
    ofast($data);
}
$time += microtime(true);
echo "Object pass by reference time: \n", sprintf('%f', $time), PHP_EOL;

function oslow($param) {
    $param->a0++;
}

function ofast(&$param) {
    $param->a0++;
}

/**
 * Array tests
 */
unset($data);
for ($i=0;$i<=999999;$i++) {
    $data['a'.$i] = $i+100000;
}

$time = -microtime(true);
for ($i=0;$i<=99;$i++) {
    slow($data);
}
$time += microtime(true);
echo "array: time: \n", sprintf('%f', $time), PHP_EOL;

$time = -microtime(true);
for ($i=0;$i<=99999;$i++) {
    fast($data);
}
$time += microtime(true);
echo "Array pass by reference time: \n", sprintf('%f', $time), PHP_EOL;

function slow($param) {
    $param['a0']++;
}

function fast(&$param) {
    $param['a0']++;
}