Clock speed refers to the frequency at which a computer's central processing unit (CPU) operates, measured in hertz (Hz). It indicates how many cycles per second the CPU can execute, with higher clock speeds generally allowing for faster processing of instructions. For example, a CPU with a clock speed of 3 GHz can perform 3 billion cycles per second. Clock speed is an important factor in determining a computer's performance, but it is not the only one. Other elements, such as the number of cores in the CPU, the architecture, and the efficiency of the software being run, also play significant roles in overall system speed and responsiveness.