The most obvious way is just to simply benchmark the two against each other. If you have a machine with each processor installed, or one machine with the ability to change the processor, then you can run tests. One machine would be better, to preserve all the other contributing aspects.

Perform some common tasks with each processor installed. These should be tasks that primarily use the CPU, rather than any other component: browsing the web wouldn't be as good, because it primarily uses the network card (yes, it *does* use CPU, but I don't see that as its *primary* resource). Tasks such as these:

- File operations (move, copy, delete);
- Heavy calculations. If you can program, make yourself a loop with some heavy work in there.

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If you don't want to do as much work, you can look up processor stats. A quick Google search revealed [this website][1], among others, to me, which seems to me to hold lists of processors that someone else has benchmarked for you.

[1]: https://www.cpubenchmark.net/