Implementation of the instruction set architecture (ISA) of the computer – the micro-architecture, is a key factor influencing performance growth in the CPU industry. The performance differences between micro-architecture variants are barely noticeable to the average user, especially if the products run at comparable clock frequencies. However, the high performance computing (HPC) industry uses thousands of microprocessors to build clusters that are required to provide a cumulative throughput of the order of millions of instructions per nano-second. In the face of growing demands on performance, nano-second level improvements in the performance of processors do make a significant difference. In order to make informed and correct decisions for purchase of high performance CPU’s, evaluation and comparison of micro-architectures is of great importance and utility to the HPC industry.