The performance of a computer can be enhanced by increasing its memory size. Memory is where the computer stores and accesses data that it needs to run programs and perform tasks. When there is not enough memory available, the computer has to use the hard drive as a substitute, which slows down its performance. By adding more memory to the computer, it can quickly access and process data, making it run faster and more efficiently. Using large monitors, faster printers, or installing a scanner do not directly enhance the computer's performance, but they can improve the user's experience and productivity.