Intel Xeon X5677 's Advantages
Higher base frequency (3.466GHz vs 3.3GHz)
Lower TDP (130W vs 140W)
Intel Xeon W 2155 's Advantages
Released 7 years and 5 months late
Higher specification of memory (DDR4-2666 vs DDR3)
Newer PCIe version (3 vs 2)
Larger L3 cache size (13.75MB vs 12MB)
More modern manufacturing process (14nm vs 32nm)