PHP: Array collection VS Class Collection

Test.php

<?php

class User
{
    protected $name;

    public function __construct($name)
    {
        $this->name = $name;
    }

    public function getName()
    {
        return $this->name;
    }
}

class UserCollection implements Iterator
{
    private $position = 0;
    private $array    = [];

    public function __construct()
    {
        $this->position = 0;
    }

    public function rewind()
    {
        $this->position = 0;
    }

    public function current()
    {
        return $this->array[$this->position];
    }

    public function key()
    {
        return $this->position;
    }

    public function next()
    {
        ++$this->position;
    }

    public function valid()
    {
        return isset($this->array[$this->position]);
    }

    public function addUser(User $user)
    {
        $this->array[] = $user;
    }
}

$totalRecord = 100000;

echo PHP_EOL . '// Class collection';
$startTime = microtime(true);
$memStart = memory_get_usage();
$list = new UserCollection();

for ($i = 1; $i <= $totalRecord; $i++) {
    $user = new User($i);
    $list->addUser($user);
}

foreach ($list as $user) {
    /** @var User $user **/
    $user->getName();
}
echo PHP_EOL . 'time:' . round(microtime(true) - $startTime, 3);
echo PHP_EOL . 'memory:' . (memory_get_usage() - $memStart);

unset($list);

echo PHP_EOL . '// Array collection';
$startTime = microtime(true);
$memStart = memory_get_usage();
$list = [];

for ($i = 1; $i <= $totalRecord; $i++) {
    $user = new User($i);
    $list[] = $user;
}

foreach ($list as $user) {
    /** @var User $user **/
    $user->getName();
}
echo PHP_EOL . 'time:' . round(microtime(true) - $startTime, 3);
echo PHP_EOL . 'memory:' . (memory_get_usage() - $memStart);