The testing environment for collecting the performance results consists of two Pentium III PCs running at 450MHz with a 100MHz memory bus, and 256MB of PC100 SD-RAM. The PCs are connected back to back via a Gigabit Ethernet NIC installed in the 32bit/33MHz PCI slot. The PCs are also connected together through a SVEC 5 port 10/100 Mbps autosensing/autoswitching hub via 3Com PCI 10/100Mbps Ethernet Cards (3c905B). Three different types of Gigabit Ethernet NICs, the Packet Engine GNIC-II, the Alteon ACEnic, and the SysKonnect SK-NET were tested. The device drivers used are Hamachi v0.07 for GNIC-II, Acenic v0.45 for ACEnic, and Sk98lin v3.01 for SK-NET. In addition, the cluster is isolated from other network traffic to ensure the accuracy of the tests. The cluster is running Red Hat 6.1 Linux distribution with kernel version 2.2.12. In addition, M-VIA v0.01, LAM v6.3, MPICH v1.1.2, and MVICH v0.02 were installed. M-VIA is an implementation of VIA for Linux, which currently supports fast Ethernet cards with DEC Tulip chipset or the Intel i8255x chipset, and the Packet Engines GNIC-I and GNIC-II Gigabit Ethernet cards. The device driver used by M-VIA is a modified version of Donald Becker's Hamachi v0.07. MVICH is a MPICH based MPI implementation for M-VIA. M-VIA and MVICH are being developed as part of the NERSC PC Cluster Project. NetPIPE-2.3 [Snell] was used to test the TCP/IP, LAM, MPICH and MVICH performance. For M-VIA tests, we used the vnettest.c, a ping-pong-like C program, distributed with the software.