Network performance evaluation is an important measurement that is used to adjust and tune up cluster systems for high-performance computing. The IBM e325, the first AMD Opteron processor-based server from IBM, is an outstanding computing power designed for HPC applications. This report summarizes the overall performance of all of the communication networks (100 Mb/s Ethernet, Gigabit Ethernet, (GigE), and Myrinet) that are available on a 16-node Linux cluster. The results indicate that changing the adapter’s default parameters and environment variables could significantly influence network performance. The Myrinet performance by far is the best in terms of high bandwidth and low latency, while the tunable GigE is better than untunable GigE. Network communications using MPI suffered certain performance loss compared to raw TCP rates.