I haven't looked very closely at the Parallella, but I don't think it's a direct comparison to this cluster. Parallella contains multiple cores on a single boar

I haven't looked very closely at the Parallella, but I don't think it's a direct comparison to this cluster. Parallella contains multiple cores on a single board, which seem to share common resources. There are two different forms of parallel processing, one for multi-core on a single node (i.e. shared RAM/peripherals), and one for multi-node (i.e. networked servers), where it can be highly impractical to share data due to the interconnections (usually Ethernet/Infiniband). In most modern clusters, you have to use both approaches. RPi 2 is nice since you have multiple cores, and the cluster shown here allows you to play with the other side of the equation, multi-node parallelism. EDIT: I looked into the parallella a bit. Still can't tell how well it represents multi-node parallelism, but it claims to have "a fast on chip network within a distributed shared memory architecture". So theoretically, this can simulate the interconnection of a large scale cluster, but I have no real knowledge of this board.