Concurrency versus parallelism in I/O-bound algorithms

As seen before, I/O-bound algorithms are constantly waiting on something else. This constant waiting allows single-core devices to use the processor to do other useful tasks while waiting. So concurrent algorithms that are I/O-bound will perform similarly regardless of the execution happening in parallel or in a single core.

It is expected that I/O-bound algorithms will always perform better in concurrent implementations than if they are sequential. So it's recommended for I/O operations to be always executed concurrently. As mentioned before, in GUI applications it's particularly important to not block the UI thread.