Генератор против массива по памяти

<?php
function makeArray(int $n): array {
    $a = [];
    for ($i = 0; $i < $n; $i++) $a[] = str_repeat('x', 100);
    return $a;
}
function makeGen(int $n): Generator {
    for ($i = 0; $i < $n; $i++) yield str_repeat('x', 100);
}
$start = memory_get_usage();
$total = 0;
foreach (makeGen(100000) as $s) $total += strlen($s);
$genMem = memory_get_peak_usage() - $start;
echo $total, "\n";
echo $genMem < 1_000_000 ? "gen: < 1 MB" : "gen: >= 1 MB", "\n";
$arr = makeArray(100000);
echo count($arr), "\n";
echo memory_get_usage() - $start > 10_000_000 ? "array: > 10 MB" : "array: <= 10 MB", "\n";