It's possible that when switching to PHP7 opcache was enabled by default, whereas it may not have been beforehand. Most likely opcache is responsible for the au

It's possible that when switching to PHP7 opcache was enabled by default, whereas it may not have been beforehand. Most likely opcache is responsible for the autoloading improvement. That said, a faster parser and intepreter would do autoloading faster as well, so it may not be opcache at all and just by virtue that the autoloaded classes are interpreted faster.