<?php
$time = microtime(true);
$c = $modx->newQuery('modResource');
$c->select(array('id','pagetitle'));
$c->where(array('id:<' => 1000));

for ($i = 1000; $i >= 0; $i--) {
    if($c->prepare() && $c->stmt->execute()) {
        $collection = $c->stmt->fetchAll(PDO::FETCH_ASSOC);
    }
    foreach ($collection as $key => $value) {
        echo '<pre>';
        print_r($value);
        echo '</pre>';
    }
}
echo microtime(true) - time(); die;