SPLFixedArray vs Array speeds

<?php

$maxSize = (int) $_GET['size'];
$times = (int) $_GET['times'];

set_time_limit(0);

echo "<h2>Number of repeated tests: " . $times . "</h2>";
echo "<table border='1'>";
echo "<thead><tr><th>Items</th><th>Time Array</th><th>Memory Array</th><th>SplFixedArray</th><th>Memory SplFixedArray</th><th>Array/SplFixedArray ratio</th><th>Speed increase by SplFixedArray</th><th>Memory reduction by SplFixedArray</th></tr></thead>";
echo "<tbody>";

for($size = 1000; $size < $maxSize; $size *= 2) {
	
	echo "<tr><td align='right'>" . $size . "</td>";
	
	$arrTotal = 0;
	$arrMemUsage = 0;
	for($time = 0; $time < $times; $time++){
		$mStart = memory_get_usage();
		$container1 = array();
		for($s = microtime(true), $i = 0; $i < $size; $i++) {
			$container1[$i] = 1;
		}
		
		$arrMemUsage += (memory_get_usage() - $mStart);
		$arrTime = (microtime(true) - $s);
		$arrTotal += $arrTime;
	}
	
	$avgArrMem = ($arrMemUsage / $times);
	$avgArr = ($arrTotal / $times);
	echo "<td align='right'>" . $avgArr  . "</td>";
	echo "<td align='right'>" . $avgArrMem . "</td>";
	// Cleanup to REDUCE the influence of memory blocks on the result
	unset($arrTotal);
	unset($arrMemUsage);
	unset($container1);
	
	$splFixedArrTotal = 0;
	$splFixedArrMemUsage = 0;
	for($time = 0; $time < $times; $time++){
		$mStart = memory_get_usage();
		$container2 = new SplFixedArray($size);
		for($s = microtime(true), $i = 0; $i < $size; $i++) {
			$container2[$i] = 1;
		}
		
		$splFixedArrMemUsage += (memory_get_usage() - $mStart);
		$splFixedArrTime = (microtime(true) - $s);
		$splFixedArrTotal += $splFixedArrTime;
	}
	
	$avgSplFixedArrMem = ($splFixedArrMemUsage / $times);
	$avgSplFixedArr = ($splFixedArrTotal / $times);
	echo "<td align='right'>" . $avgSplFixedArr . "</td>";
	echo "<td align='right'>" . $avgSplFixedArrMem . "</td>";
	// Cleanup to REDUCE the influence of memory blocks on the result
	unset($splFixedArrTotal);
	unset($splFixedArrMemUsage);
	unset($container2);
	
	// Calculate ratio
	echo "<td align='right'>" . ($avgArr / $avgSplFixedArr) . "</td>";
	// Calculate speed increase percentage
	echo "<td align='right'>" . number_format(((($avgSplFixedArr - $avgArr) / $avgArr) * -100), 4) . " %</td>";
	// Calculated memory reduction percentage
	if ($avgArrMem == 0){
		echo "<td align='right'>NaN</td></tr>";
	}
	else {
		echo "<td align='right'>" . number_format(((($avgSplFixedArrMem - $avgArrMem) / $avgArrMem) * -100), 4) . " %</td></tr>";
	}
	
	// Cleanup to REDUCE the influence of memory blocks on the result
	unset($avgArr);
	unset($avgSplFixedArr);

}

echo "</tbody></table>";

?>