+1 to what Fumz said.
I'd see whatever your Highest stalbe OC is at with settings at 1.4v and stay there. anything higher your loosing life span. unless your Wanting to fry it so you can upgrade. then go for 1.6 and enjoy it While it lasts. but thats not recommended.
I have my Quad at 3.5 GHz runs at 1.384v