Adding Processors Does Not Always Speed Up Tasks
Adding more computers to a single task often provides diminishing returns rather than a linear speed boost. As processors work together, they eventually spend more time coordinating than actually solving the problem.
When you increase the number of processors, the overhead for managing communication between them grows significantly. Eventually, the effort to keep all threads synchronized outweighs the benefit of parallel calculation. This phenomenon is known as Amdahls Law, which proves that the serial part of any program limits how much faster it can run. It is a constant tug-of-war between raw computing power and the complexity of teamwork.
Source: Analysis of parallel algorithms