IPC, or instructions per clock. So how many instructions it can process per Hz.
And which instructions it supports. For example AVX512 can speed up bulk data processing in specific applications that support it.
With all these complications the only way to really compare CPUs accurately is to benchmark the programs or games you intend to run on them. Obviously this is not realistic so reviewers benchmark a few varied real world programs, games and artificial tests. Those results usually extrapolate fairly well to other, similar software.
IPC, or instructions per clock. So how many instructions it can process per Hz. And which instructions it supports. For example AVX512 can speed up bulk data processing in specific applications that support it.
With all these complications the only way to really compare CPUs accurately is to benchmark the programs or games you intend to run on them. Obviously this is not realistic so reviewers benchmark a few varied real world programs, games and artificial tests. Those results usually extrapolate fairly well to other, similar software.