use strict;
use warnings;
use Benchmark qw(cmpthese);

my @strings;

for(my $i=0;$i<1000;$i++)
  {
    $strings[$i] = (sprintf("%06d",$i)) x rand(1000);
  }

my $asign1;
my $asign2;

cmpthese
    (-1,
        {
        pack => sub {$asign2 = pack("a*" x($#strings + 1),@strings)},
        join => sub {$asign1 = join '', @strings},
        }
    );