I get the array ref faster than the split, though sometimes only marginally so. It appears that you code is incomplete. Here is the code I used:

#!/usr/bin/perl -w
use strict;
use Benchmark qw(timethese);

my $Regexp = qr/,/;

sub try_split
  {
    my ($arg) = @_;
    return split $Regexp, $arg;
  }

sub try_arrayref
  {
    my ($arg) = @_;
    return @$arg;
  }

my @arr= '00'..'99';
#my @arr= '0'..'9';
#my @arr= '0'..'3';
my $str= join ",", @arr;
my @x;
timethese( -3, {
    split=>sub{@x= try_split($str)},
    aref=>sub{@x= try_arrayref(\@arr)}
} );
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        - tye (but my friends call me "Tye")