Drupal is fantastic at caching itself (I mean, you've gotta be with a code base this hefty).  Drupal 8 will see the dawn of render cache in core which is why most metrics you see of D8 are uncached (because it's basically cheating its so fast cached). If you want to play around with Render Cache in D7, it can be done but still needs some work (Drupal.org actually runs Render Cache backport to handle comments in issue queues among other things).