Intel Xeon D 1518 's Advantages
More modern manufacturing process (14nm vs 22nm)
Lower TDP (35W vs 135W)
Intel Xeon E5 2666 v3 's Advantages
Higher specification of memory (DDR4-2133 vs DDR3)
Higher base frequency (2.9GHz vs 2.2GHz)
Larger L3 cache size (25MB vs 1.5MB)