Intel Xeon D 1521 's Advantages
Released 10 months late
Higher base frequency (2.4GHz vs 2GHz)
More modern manufacturing process (14nm vs 22nm)
Lower TDP (45W vs 135W)
Intel Xeon E5 2698B v3 's Advantages
Higher specification of memory (DDR4-2133 vs DDR3)
Larger L3 cache size (40MB vs 1.5MB)