The ideal E7-4850v3 is outperformed by their v2 counterpart E7-4890v2 in nearly every aspect (clock speed, cores).
It is still unclear how the QPI links are connected when using an E7-88xx chipset in a four socket server, and it is yet to be tested. If the results for those are good then the ET-8890 v3 could be a solid option, but again it is not tested by us.
I'd recommend having them going for E7-4890 v2 or similar, which are proven to be good.
I know this is an old Thread, but if anyone else is facing this issue i would suggest ignoring the E7s and go with the E5 isnstead. The E5s have enough cores for almost all installations of QV. If you are building a Publisher then you should go with higher clockspeed and lower core count (Like 2643v4,2667v4 or 2689v4). For a QVS you could use more cores but i would not go over 32 physical cores. After that you could go with higher clockspeed (like two 2684v4)