My 4.6GHz 4820K vs my 4GHz 1920X. Gen 1 zen certainly has ivybridge-E beaten even with a 600MHz clock deficit in Cinebench.
One thing to bare in mind here - IvyBridge-E for stuff like Cinebench performs best at 2133-2400MHz with tight timings - though not a huge deal you will easily actually lose 1-2% with faster RAM (and looser timings) and possibly even as much as 5% down at 1600MHz CL9 versus faster RAM.