We evaluate and compare the performance of LAM, MPICH, and MVICH on a Linux cluster connected by a Gigabit Ethernet network. Performance statistics are collected using NetPIPE which show the behavior of LAM/MPI and MPICH over a gigabit network. Since LAM and MPICH use the TCP/IP socket interface for communicating messages, it is critical to have high TCP/IP performance. Despite many efforts to improve TCP/IP performance, the performance graphs presented here indicate that the overhead incurred in protocol stack processing is still high. Recent developments such as the VIA-based MPI implementation MVICH can improve communication throughput and thus give the promise of enabling distributed applications to improve performance.