Xeon L5639 's Advantages
Higher specification of memory (1333 vs 3)
Higher base frequency (2.133GHz vs 2GHz)
Lower TDP (60W vs 95W)
Intel Xeon E5 2640 v2 's Advantages
Released 2 years and 7 months late
Newer PCIe version (3 vs 2)
Larger L3 cache size (20MB vs 12MB)
More modern manufacturing process (22nm vs 32nm)