Whatever 5820k you get, its only guaranteed to be a 5820k, nothing more. That means it'll run stable at the 3.3GHz (as stable as any Windows system can be) that the 5820k comes stock with. How far past that OC will go is anyone's guess, not even batch numbers have any real success, but J chips seem to do better than L. I've seen posts of ppl with nh-d14 and h100i and the Phanteks PH-TC14PE taking their 5820k to 4.7GHz at 1.3v, the jump to 4.8GHz being to big to be worth the heat.
So chances are, you'll land anywhere from 3.3GHz to @ 4.7GHz. Just where, nobody knows, no by can predict, and thats as much as I will legally say on not reaching OC goals.
Overclocking, by definition, voids most warranties, even Intel. It's funny how ppl like Asus build boards for OC purposes, give you software designed to OC a cpu, knowing fully that any OC will void the Intel warranty if the cpu needs to be RMA (for whatever reason)