$ perl test.pl
              Rate unpack substr  split
unpack 171232877/s     --   -23%   -31%
substr 223713647/s    31%     --   -10%
split  248138958/s    45%    11%     --

##</code><code>##

karls-mac-mini:monks karl$ perl -e 'printf ("%.1f\n", 248138958/171232877);'
1.4