Chunk File

gistfile1.php

<?php

/**
 * This function will read the file passed to it at 1MB/s and output it to the
 * browser.
 */
function readfile_chunked( $filename )
{
    $rate = 1024;

    $file = fopen($filename, 'rb');

    while( !feof($file) )
    {
        print fread($file, round($rate * 1024));
        flush();
        ob_flush();
        sleep(1);
    }

    fclose($file);
    exit;
}

$file = 'http://domain.com/path/to/file.extension';
readfile_chunked($file);