PVM uses round-robin as its default policy for process allocation to processors. The main drawbacks of this policy are the fact that PVM ignores load variations among different nodes and also the inability of PVM to distinguish between machines of different speeds. To redress this deficiency a Resource Manager (RM) is implemented which replaces round-robin with a scalable and adaptive algorithm for resource sharing [11] providing a High Performance Computing Cluster (HPCC). In this paper an implementation of a Resource Manager is proposed. The RM can be transparently plugged into PVM to offer improved performance to its users. The design of a resource manager to extend PVM is described. A prototype implementation in PVM is then measured to illustrate the utility of the approach. Finally, performance results favorably comparing the enhanced version to the original PVM are presented ...