From efficiency point of view our next mobos should be Quad SuperMicro's with four 16-core Opteron Opteron 6262 HE.
They need just 65(ACP)-85(TDP) Watt for those 16 cores. You can fill the mobo's with 512 Gb RAM (ECC Registered, Oké),
and it has a PCI-E (16) slot, so with a DDR3 HD 6670 it costs next to nothing to crunch 64 CPU WUs, 64 FreeHALs, 1 WuProp,
and -with the aid of a smart app_inbfo.xml- two GPU WUs= 131 processes at a time!