I have a small cluster with 8 nodes. All the nodes have the same specification in terms of the CPU but the amount of RAM each has. I would like to add to the queue some spare computers as well. However, these computers do not have the same specifications(different CPU brand, # of cores and freq. etc) as that of the nodes. Would appreciate it if anyone inform me if this could be a performance issue for the cluster or it does not matter at all?