Intel Xeon E5649 's Advantages
Larger L3 cache size (12MB vs 11MB)
Lower TDP (80W vs 140W)
Intel Xeon W 2145 's Advantages
Released 6 years and 6 months late
Higher specification of memory (DDR4-2666 vs DDR3)
Newer PCIe version (3 vs 2)
Higher base frequency (3.7GHz vs 2.533GHz)
More modern manufacturing process (14nm vs 32nm)