Intel Xeon X5672 's Advantages
Higher base frequency (3.2GHz vs 2.4GHz)
Larger L3 cache size (12MB vs 1.5MB)
Intel Xeon D 1521 's Advantages
Released 4 years and 9 months late
Higher specification of memory (4 vs 3)
Newer PCIe version (3 vs 2)
More modern manufacturing process (14nm vs 32nm)
Lower TDP (45W vs 95W)