<?php
    $repetitions = 2000000;

    $item = 'Hallo';
    $pow = 'was';
    $sit = 'geht?';

    $test = '';

    $time = microtime(true);
    for($i=0;$i<$repetitions;$i++)
        $test = "{$item} {$pow} {$sit}";
    echo '1. Curly Braces: ' . (microtime(true)-$time) . '<br>';

    $time = microtime(true);
    for($i=0;$i<$repetitions;$i++)
        $test = "$item $pow $sit";
    echo '2. Inline: ' . (microtime(true)-$time) . '<br>';

    $time = microtime(true);
    for($i=0;$i<$repetitions;$i++)
        $test = $item . " " . $pow . " " . $sit;
    echo '3. Concatenate Doublequote: ' . (microtime(true)-$time) . '<br>';

    $time = microtime(true);
    for($i=0;$i<$repetitions;$i++)
        $test = $item . ' ' . $pow . ' ' . $sit;
    echo '4. Concatenate Singlequote: ' . (microtime(true)-$time);