Think of processing power as the ability to think quickly, memory as the ability to retain short-term memory, and hard drive space as the ability to retain long-term memory. When you run a program, the speed at which it runs is controlled by both processing power and memory. When you save files, the number of files you can save relates to the hard drive. Many real estate agents are going to need decent power, memory, and hard drive space. Apart from this, you’ll also need decent battery life — or to bring a battery backup.