Intel Xeon D 1520 's Advantages
Released 10 months late
More modern manufacturing process (14nm vs 22nm)
Lower TDP (45W vs 84W)
Intel Xeon E3 1226 v3 's Advantages
Higher specification of memory (1600 vs 4)
Higher base frequency (3.3GHz vs 2.2GHz)
Larger L3 cache size (8MB vs 1.5MB)