Xeon E5540 's Advantages
Higher base frequency (2.533GHz vs 2.3GHz)
Lower TDP (80W vs 120W)
Intel Xeon E5 2669 v3 's Advantages
Released 5 years and 10 months late
Higher specification of memory (2133 vs 1066)
Newer PCIe version (3 vs 2)
Larger L3 cache size (30MB vs 8MB)
More modern manufacturing process (22nm vs 45nm)