Intel Xeon D 1520 's Advantages
Released 4 years and 1 months late
Newer PCIe version (3 vs 2)
Higher base frequency (2.2GHz vs 2.133GHz)
More modern manufacturing process (14nm vs 32nm)
Lower TDP (45W vs 60W)
Xeon L5639 's Advantages
Higher specification of memory (1333 vs 4)
Larger L3 cache size (12MB vs 1.5MB)