For the moment (well, february) the improvement with PHP 8.0 JIT is minimal: https://www.phoronix.com/scan.php?page=news_item&px=PHP-8.0-Performance-Bench-2020

For the moment (well, february) the improvement with PHP 8.0 JIT is minimal: https://www.phoronix.com/scan.php?page=news_item&px=PHP-8.0-Performance-Bench-2020 https://www.phoronix.com/scan.php?page=news_item&px=PHP-8.0-... But usually a JIT is made in a way that you can then move forward with your optimizations in small tested steps. So it makes sense for JITv1 to have a very similar performance as the non-JITed version. It probably generates highly familiar code. First make it do the same, then optimize.