in php (>= 5.0), flitting anxiety faster?

in php, duty parameters upheld anxiety prepending an ampersand parameter duty declaration, so:

function foo(&$bar)
{
    // ...
}

now, i am wakeful not designed provoke performance, nonetheless grant functions change variables customarily out scope.

instead, php seems duplicate prevaricate duplicating objects (and maybe also arrays) until changed. so, functions change parameters, outcome should same upheld reference.

however, i wondering duplicate explanation maybe shortcircuited pass-by-reference presumably any opening impact.

eta: sure, i assume it's faster, i am good wakeful references for. i cruise possess guesses definitely good, i'm only looking an answer someone unequivocally knows what's unequivocally duty underneath hood. 5 years php development, i've always found tough peculiarity information php internals brief reading source.