Xeon E7 8860 's Advantages
Higher specification of memory (1333 vs 4)
Higher base frequency (2.266GHz vs 2.2GHz)
Larger L3 cache size (24MB vs 1.5MB)
Intel Xeon D 1520 's Advantages
Released 3 years and 11 months late
More modern manufacturing process (14nm vs 32nm)
Lower TDP (45W vs 130W)