It is clear that in-memory operations available in SparkBLAST plays a major role both in Speedup and Parallel Efficiency improvements and, as a consequence, also in the scalability of the system. Indeed, the main reason behind the fact that SparkBLAST, even when it allocates only half of nodes processing capacity, achieves performance figures that are superior of those of CloudBLAST is the reduced number of local I/O operations.