Intel Xeon D 1521 's Advantages
Lower TDP (45W vs 150W)
Intel Xeon Gold 5415 's Advantages
Released 7 years and 2 months late
Higher specification of memory (DDR5-4400 vs DDR3)
Newer PCIe version (5 vs 3)
Higher base frequency (2.9GHz vs 2.4GHz)
Larger L3 cache size (22.5MB vs 1.5MB)
More modern manufacturing process (10nm vs 14nm)