Magento Set reviews limit on product page

Copy /app/code/core/Mage/Review/Block/Product/View/View.php to
 /app/code/local/Mage/Review/Block/Product/View.php. with following code :-

Find the function getReviewsCollection() and replce with below function.

public function getReviewsCollection()
    {
        if (null === $this->_reviewsCollection) {
            $this->_reviewsCollection = Mage::getModel('review/review')->getCollection()
                ->addStoreFilter(Mage::app()->getStore()->getId())
                ->addStatusFilter(Mage_Review_Model_Review::STATUS_APPROVED)
                ->addEntityFilter('product', $this->getProduct()->getId())
                ->setDateOrder();
                $this->_reviewsCollection->getSelect()->limit(5);
        }
        return $this->_reviewsCollection;
    }