Xeon E7 8870 's Advantages
Higher specification of memory (1333 vs 4)
Higher base frequency (2.4GHz vs 1.7GHz)
Larger L3 cache size (30MB vs 1.5MB)
Intel Xeon D 1587 's Advantages
Released 4 years and 10 months late
More modern manufacturing process (14nm vs 32nm)
Lower TDP (65W vs 130W)