CPU bound vs IO bound

From stackoverflow: What do the terms “CPU bound” and “I/O bound” mean?:

• CPU Bound means the rate at which process progresses is limited by the speed of the CPU.
  • A task that performs calculations on a small set of numbers, for example multiplying small matrices, is likely to be CPU bound.
  • A program is CPU bound if it would go faster if the CPU were faster.
• I/O Bound means the rate at which a process progresses is limited by the speed of the I/O subsystem.
  • A task that processes data from disk, for example, counting the number of lines in a file is likely to be I/O bound.
  • A program is I/O bound if it would go faster if the I/O subsystem was faster.