<?php
ini_set('memory_limit','64M');
$s=str_repeat("xD", 100);
function hash_part($start,$length) {
        $ctx = hash_init('md5');
 
        $ch = "";
        $remaining=$length;
        while ($remaining > 0) {
                //$data = fread($fp, $chunkSize);
                $data = $GLOBALS['s'];
               
                $read = hash_update($ctx, $data);
                $ch .= $data;
               
                $remaining -= strlen($data);
        }
        return hash_final($ctx) . " : " . md5($ch);
}
for($i=0;$i<100;$i++)
echo hash_part(0,40*1024*1024) . "\n";
?>
Output:
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 30dacffb204a6440440a99c729ba2220
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 16d1f706be58add6f03f0822a6f9369b
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 031721f72b99e579d289c0466267ac76
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 5413b2a62735e8b2887c8ebe0e1da650
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 16d1f706be58add6f03f0822a6f9369b
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
30dacffb204a6440440a99c729ba2220 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 4cbd713d6c8bf2639767d9dd05c22445
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 18906f801c126237e485bdb3b5e23e73
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 16d1f706be58add6f03f0822a6f9369b
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : b691624446633d9da3a66b29b974fdec
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
034c00ce62aa68a451909a17c87a18b3 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 034c00ce62aa68a451909a17c87a18b3
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
031721f72b99e579d289c0466267ac76 : 41413b9830f0f113e6283c8ee54e7c56
d4778acdca2147d30717ad22349154b0 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : a341a8a80e23b7cd14726eac3d4956b3
16d1f706be58add6f03f0822a6f9369b : 41413b9830f0f113e6283c8ee54e7c56
41413b9830f0f113e6283c8ee54e7c56 : 41413b9830f0f113e6283c8ee54e7c56