Intel Xeon L5609 's Advantages
Higher base frequency (1.866GHz vs 1.7GHz)
Larger L3 cache size (12MB vs 1.5MB)
Lower TDP (40W vs 65W)
Intel Xeon D 1587 's Advantages
Released 5 years and 11 months late
Higher specification of memory (4 vs 3)
Newer PCIe version (3 vs 2)
More modern manufacturing process (14nm vs 32nm)