Intel Xeon X5660 Advantages
Higher base frequency (2.8GHz vs 2.5GHz)
Lower TDP (95W vs 175W)
Xeon 6523P B Advantages
Released 14 years and 11 months late
Higher specification of memory (5600 vs 3)
Newer PCIe version (5 vs 2)
Larger L3 cache size (96MB vs 12MB)
More modern manufacturing process (5nm vs 32nm)