PHP - Xml Speeding Up

Hi all,
I've been trying to build a php instant search and using an xml file to show 10 items matching items, all works fine but the xml file has over 5000 titles and urls in it so it takes about 10 seconds to show any results. Does any one know how i can speed things up?

The bit of code i'm using ->
Code: [Select]
<?php
$xmlDoc=new DOMDocument();
$xmlDoc->load("links.xml");

$x=$xmlDoc->getElementsByTagName('link');

//get the q parameter from URL
$q=$_GET["q"];

//lookup all links from the xml file if length of q>0
if (strlen($q)>0)
{
$hint="";

for($i=0; $i<($x->length); $i++)
  {
  
  $y=$x->item($i)->getElementsByTagName('title');
  $z=$x->item($i)->getElementsByTagName('url');
 $limit = 10;
  if ($y->item(0)->nodeType==1)
    {
    //find a link matching the search text
    if (stristr($y->item(0)->childNodes->item(0)->nodeValue,$q))
      {
      if ($hint=="")
        {

        $hint="<a href='" . 
        $z->item(0)->childNodes->item(0)->nodeValue . 
        "' target='_blank'>" . 
        $y->item(0)->childNodes->item(0)->nodeValue . "</a>";
        }
      else
        {
if($counter <= $limit) {
        $hint=$hint . "<br /><a href='" . 
        $z->item(0)->childNodes->item(0)->nodeValue . 
        "' target='_blank'>" . 
        $y->item(0)->childNodes->item(0)->nodeValue . "</a>";
        $counter++; }}
      }
    } 
  }
  
}

// Set output to "no suggestion" if no hint were found
// or to the correct values
if ($hint=="")
  {
  $response="no suggestion";
  }
else
  {
  $response=$hint;
  }

//output the response
echo $response;
?>
Cheers all