Скорость eval и анонимных функций

$count = 50;
$start = microtime(true);
$y = 0;
for($i = 0; $i < $count; $i++)
{
    eval('++$y;');
}
 
printf("#1, result is %d, done in %f\n", $y, microtime(true) - $start);
 
$start = microtime(true);
$y = 0;
for($i = 0; $i < $count; $i++)
{
    $f = function() use (&$y)
    {
        return ++$y;
    };
    $f();
}
 
printf("#2, result is %d, done in %f\n", $y, microtime(true) - $start);

d:\src>php callback_performance.php
#1, result is 50, done in 0.000415
#2, result is 50, done in 0.000270
 
d:\src>php callback_performance.php
#1, result is 50, done in 0.000413
#2, result is 50, done in 0.000261
 
d:\src>php callback_performance.php
#1, result is 50, done in 0.000412
#2, result is 50, done in 0.000273