There must be something unusual about OP's data. A simple test gives very similar results for the two techniques:

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

my $target =
  'Some leading text' .
  'chrMatchTextForChr ' .
  'Some text to be ignored following chr ' .
  'urn:lsid:UrnLisdMatchText ' .
  'Text to be ignored after urn:lsid match text' .
  'panel:Text: Some text that doesn\'t get matched by anything';

die "Different results" if all () ne parts ();

cmpthese (-1, {'all' => \&all, 'parts' => \&parts});

sub all
{
my ($chr,$prot,$panel) = $target =~ /(chr.*?)\s.*urn:lsid:(.*?)\s.*pan
+el:(.*?):/i;
return "$chr$prot$panel";
}

sub parts
{
my ($chr) = $target =~ /(chr.*?)\s/i;
my ($prot) = $target =~ /urn:lsid:(.*?)\s/i;
my ($panel) = $target =~ /panel:(.*?):/i;
return "$chr$prot$panel";
}

Prints:

         Rate parts   all
parts 82116/s    --  -17%
all   98443/s   20%    --

[download]
Perl is Huffman encoded by design.

In reply to Re: Regex, capturing variables vs. speed by GrandFather
in thread Regex, capturing variables vs. speed by albert

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