$ php -d implicit_flush=off -r '$s=microtime(true); for($i=0;$i<100000;$i++) echo "omgwtf","bbq","\n"; echo microtime(true)-$s;' | tail -n 1
1.071463108062710
$ php -d implicit_flush=off -r '$s=microtime(true); for($i=0;$i<100000;$i++) echo "omgwtf"."bbq"."\n"; echo microtime(true)-$s;' | tail -n 1
0.44555306434631