Intel Xeon E5 2609 's Advantages
Released 3 years late
Newer PCIe version (3 vs 2)
Larger L3 cache size (10MB vs 8MB)
More modern manufacturing process (32nm vs 45nm)
Lower TDP (80W vs 130W)
Xeon W5580 's Advantages
Higher specification of memory (1333 vs 3)
Higher base frequency (3.2GHz vs 2.4GHz)