Intel Xeon E5 2666 v3 's Advantages
Higher base frequency (2.9GHz vs 2.8GHz)
Larger L3 cache size (25MB vs 24MB)
Xeon E 2478 's Advantages
Released 9 years and 1 months late
Higher specification of memory (4800 vs 2133)
Newer PCIe version (5 vs 3)
More modern manufacturing process (10nm vs 22nm)
Lower TDP (80W vs 135W)