Intel Xeon D 1520 's Advantages
Released 6 years and 6 months late
More modern manufacturing process (14nm vs 45nm)
Lower TDP (45W vs 90W)
Xeon X7458 's Advantages
Higher specification of memory (667 vs 4)
Higher base frequency (2.4GHz vs 2.2GHz)
Larger L3 cache size (16MB vs 1.5MB)