How does it improve performance?

Using xargs -n improves performance in several ways:

Reduced Process Overhead: Each time a command is executed, there is a certain amount of overhead associated with starting a new process. By grouping multiple arguments together and executing the command fewer times, xargs -n minimizes this overhead, leading to faster execution.
Efficient Resource Utilization: When commands are invoked less frequently, system resources such as CPU and memory are used more efficiently. This is particularly important when processing large datasets or numerous files, as it reduces the strain on system resources.
Batch Processing: By processing multiple items in a single command execution, xargs -n allows for batch processing. This can significantly speed up operations, especially for commands that can handle multiple inputs at once, such as cp, mv, or rm.
Improved I/O Performance: For commands that involve input/output operations (like file manipulation), reducing the number of times the command is called can lead to better I/O performance. This is because the system can optimize the handling of data when it processes it in larger chunks rather than individually.
Parallel Execution: When combined with the -P option, xargs can run multiple instances of a command in parallel, further enhancing performance. This allows for concurrent processing of batches, which can significantly reduce overall execution time.

Overall, xargs -n enhances performance by optimizing how commands are executed, reducing overhead, and making better use of system resources, especially when dealing with large volumes of data.