Interpreters and compilers serve to translate high-level source code into machine code, but they operate differently. An interpreter translates and executes code line-by-line, making it slower and less efficient, while a compiler translates the entire source code into machine code, creating an executable file that can be run multiple times without recompilation. Compilers optimize code during this process, which can significantly enhance execution speed and efficiency by integrating necessary libraries and reducing the need for repeated disk access. Additionally, compilers can handle error checking and exception management more effectively than interpreters. Overall, the choice between using an interpreter or a compiler often depends on the specific needs for speed and flexibility in programming.