Hey man!
If your cpu can't OC more at 1.4v then you have hit your limits. And if your Input / VRIN is at 2v or so there shouldnt be much else you need. Sounds about right.
Your score however is really low, there is something causing a broken run, should be over 1000 easy. There is a high chance your cpu is throttling and getting too warm, if you got 636 at 3900 and only 657 now go look at your cpu load and see if its 100% through the whole test