Intel Xeon D 1587 's Advantages
Lower TDP (65W vs 140W)
Intel Xeon W 2155 's Advantages
Released 1 years and 6 months late
Higher specification of memory (DDR4-2666 vs DDR3)
Higher base frequency (3.3GHz vs 1.7GHz)
Larger L3 cache size (13.75MB vs 1.5MB)