Xeon E6540 's Advantages
Higher specification of memory (1333 vs 3)
Intel Xeon E5 2650 's Advantages
Released 2 years late
Newer PCIe version (3 vs 2)
Larger L3 cache size (20MB vs 18MB)
More modern manufacturing process (32nm vs 45nm)
Lower TDP (95W vs 105W)