Magento how to cache a productCollection

Question

Ive noticed my home page is taking a long time to load - over 6 seconds infact according site24x7.com, so ive been switching elements off to try and determine what is the cause,

Answer 1

If you want to cache $collection, there is already a built-in possibility for collection caching in Magento.

 $_productCollection= Mage::getResourceModel('reports/product_collection');

$cache = Mage::app()->getCache(); //Let's get cache instance
        $cache->setLifetime(86400); //Here we set collection cache lifetime
        $_productCollection->initCache(
            $cache,
            'Bestsellers_', //this is just custom prefix
            array('collections') 
        );
    }

Credit for above code: apiworks.net (http://www.apiworks.net/2015/01/magento-collection-caching.html)