Не оправдано большой кеш страниц.

public function getElement($class, $name) {
    $realname = $this->realname($name);
    if (array_key_exists($class, $this->modx->sourceCache) && array_key_exists($realname, $this->modx->sourceCache[$class])) {
        /** @var modElement $element */
        $element = $this->modx->newObject($class);
        $element->fromArray($this->modx->sourceCache[$class][$realname]['fields'], '', true, true);
        $element->setPolicies($this->modx->sourceCache[$class][$realname]['policies']);

        if (!empty($this->modx->sourceCache[$class][$realname]['source'])) {
            if (!empty($this->modx->sourceCache[$class][$realname]['source']['class_key'])) {
                $sourceClassKey = $this->modx->sourceCache[$class][$realname]['source']['class_key'];
                $this->modx->loadClass('sources.modMediaSource');
                /* @var modMediaSource $source */
                $source = $this->modx->newObject($sourceClassKey);
                $source->fromArray($this->modx->sourceCache[$class][$realname]['source'],'',true,true);
                $element->addOne($source,'Source');
            }
        }
    } else {
        /** @var modElement $element */
        $element = $this->modx->getObjectGraph($class,array('Source' => array()),array('name' => $realname), true);
        if ($element && array_key_exists($class, $this->modx->sourceCache)) {
            $this->modx->sourceCache[$class][$realname] = array(
                'fields' => $element->toArray(),
                'policies' => $element->getPolicies(),
                'source' => $element->Source ? $element->Source->toArray() : array(),
            );
        }
    }
    if ($element instanceof modElement) {
        $element->set('name', $name);
    }
    return $element;
}

$fields = $element->toArray();
unset($fields['snippet']);
unset($fields['content']);
$this->modx->sourceCache[$class][$realname] = array(
    'fields' => $fields,
    'policies' => $element->getPolicies(),
    'source' => $element->Source ? $element->Source->toArray() : array(),
);