Intel Xeon E5 1681 v3 's Advantages
Larger L3 cache size (25MB vs 13.75MB)
Lower TDP (135W vs 140W)
Intel Xeon W 2155 's Advantages
Released 2 years and 11 months late
Higher specification of memory (2666 vs 2133)
Higher base frequency (3.3GHz vs 2.9GHz)
More modern manufacturing process (14nm vs 22nm)