  We describe a new 512-CPU Beowulf cluster with Teraflop performance dedicated
to problems in computational astrophysics. The cluster incorporates a cubic
network topology based on inexpensive commodity 24-port gigabit switches and
point to point connections through the second gigabit port on each Linux
server. This configuration has network performance competitive with more
expensive cluster configurations and is scaleable to much larger systems using
other network topologies. Networking represents only about 9% of our total
system cost of USD$561K. The standard Top 500 HPL Linpack benchmark rating is
1.202 Teraflops on 512 CPUs so computing costs by this measure are
$0.47/Megaflop. We also describe 4 different astrophysical applications using
complex parallel algorithms for studying large-scale structure formation,
galaxy dynamics, magnetohydrodynamic flows onto blackholes and planet formation
currently running on the cluster and achieving high parallel performance. The
MHD code achieved a sustained speed of 2.2 teraflops in single precision or 44%
of the theoretical peak.
