Before revision:  Here we present a multi-level approach to identifying the performance gap between HPC and cloud computing and to isolate several variables that contribute to this gap by dividing our experiments into (i) hardware and system microbenchmarks and (ii) user applications. Our results show that today's high-end cloud computing can deliver HPC-like performance - at least at modest scales - not only for computationally intensive applications , but also for memory- and communication-intensive applications , thanks to the high-speed memory systems and interconnects and dedicated batch scheduling now available on some cloud platforms.
After revision:  Here we present a multi-level approach to identifying the performance gap between HPC and cloud computing and to isolate several variables that contribute to this gap by dividing our experiments into (i) hardware and system microbenchmarks and (ii) user application proxies. The results show that today's high-end cloud computing can deliver HPC-like performance - at least at modest scales - not only for computationally intensive applications , but also for memory- and communication-intensive applications , thanks to the high-speed memory systems and interconnects and dedicated batch scheduling now available on some cloud platforms.