It's not the biggest I've seen through the years [at WCG, ACAH 1 was big too] and fortunately a one-time download. Since the app is one-time, more of interest is the memory use. 1GB RAM requirement and 2 GB disk is big, per concurrent task. Looking at the graphics and the high definition... there's masses of information computed and simulated, the times having arrived that scientists are not going to be worrying about resource use, rather the highest possible resolution, at speed... we do want to find that element mix and configuration to be able to simulate the PV optimum that nature achieves, hands down.