PostgresSQL replace vs regexp_replace benchmark

bench.sql

CREATE OR REPLACE FUNCTION benchmark() RETURNS INTEGER AS
$BODY$
BEGIN
  FOR i IN 1..10000000 LOOP
    PERFORM replace(replace('Lorem %ipsum_dolor sit amet, %consectetu%r_adipisici%ng elit,_sed do eiusmod', '%', '\%'), '_', '\_');
  END LOOP;
  return 1;
END
$BODY$
LANGUAGE 'plpgsql' ;

SELECT benchmark() as replace;

CREATE OR REPLACE FUNCTION benchmark() RETURNS INTEGER AS
$BODY$
BEGIN
  FOR i IN 1..10000000 LOOP
    PERFORM regexp_replace('Lorem %ipsum_dolor sit amet, %consectetu%r_adipisici%ng elit,_sed do eiusmod', '(%|_)', '\\\1', 'g');
  END LOOP;
  return 1;
END
$BODY$
LANGUAGE 'plpgsql' ;

SELECT benchmark() as regexp_replace1;

replace: 14.989 s
regexp_replace: 15.243 s