When you are choosing a CPU, there are two main specifications you need to pay attention to that define the relative performance of two CPUs based on the same architecture: frequency and number of cores. While hardware review sites like TechSpot do a great job testing and comparing different CPUs, unless they specifically benchmark the applications you personally use their results may not accurately reflect the performance that you would see.
If your software only uses a single core, the frequency is a decent indicator of how well a CPU will perform. However, if your software is able to utilize multiple CPU cores it becomes very difficult to estimate the performance of different CPU models since almost no program is going to be 100% efficient at using those cores. The trick is to determine exactly how efficient your program is at using multiple CPU cores (it's parallelization efficiency) and use that number to estimate the performance of different CPU models.
To calculate the parallelization efficiency, you need to use a mathematical equation called Amdahl's Law. Don't worry, though, we'll give you the theory but for those that don't particularly love math there's an "Easy Mode" spreadsheet.
