20 words:

              Rate stringify      join
stringify 155272/s        --      -29%
join      219556/s       41%        --


51 words:

             Rate stringify      join
stringify 83452/s        --      -16%
join      99407/s       19%        --


2000 words:

            Rate stringify      join
stringify 2736/s        --       -3%
join      2813/s        3%        --