  With the increasing number of Quad-Core-based clusters and the introduction
of compute nodes designed with large memory capacity shared by multiple cores,
new problems related to scalability arise. In this paper, we analyze the
overall performance of a cluster built with nodes having a dual Quad-Core
Processor on each node. Some benchmark results are presented and some
observations are mentioned when handling such processors on a benchmark test. A
Quad-Core-based cluster's complexity arises from the fact that both local
communication and network communications between the running processes need to
be addressed. The potentials of an MPI-OpenMP approach are pinpointed because
of its reduced communication overhead. At the end, we come to a conclusion that
an MPI-OpenMP solution should be considered in such clusters since optimizing
network communications between nodes is as important as optimizing local
communications between processors in a multi-core cluster.
