@Marvin: not sure I understand the “bad news” part. The cost per socket is determined by the processor exact model, not by generation.
For example, if you wanted to use a processor with AVX enabled, you could choose E5-2630v2 (latest generation Xeon, until the v3’s are released).
That gives you (on each socket) 6 cores running in 2.6GHz, with AVX. That’s not a weak compute capability by any measure.