Before we get into the formula for Amdahl's Law and its implications, let's explore the concept of speedup, through some brief analysis. Let's assume that there are N workers working on a given job that is fully parallelizable—that is, the job can be perfectly divided into N equal sections. This means that N workers working together to complete the job will only take 1/N of the time it takes one worker to complete the same job.
However, most computer programs are not 100% parallelizable: some parts of a program might be inherently sequential, while others are broken up into parallel tasks.