What is more decisive for CPU performance: the number of cores or the clock frequency? Unfortunately, there is no clear answer to this question. It not only depends on the application, but also on the processor itself.
Modern processors are often more efficient in processing instructions and can therefore also provide the same performance with a lower clock frequency as older processors with a higher clock frequency. In addition, modern processors often offer the possibility for multithreading or hyperthreading, so that several threads can be executed in parallel on one core.
If you run applications on your computer that benefit from multiple cores and parallelization, then it is worthwhile to resort to a correspondingly high number of processor cores to distribute the CPU load in the best possible way. Such applications include the use of virtual machines or rendering. This is because the workload of such programs can be distributed very well.
If you mainly use your PC for applications that can’t distribute their workload that well, for example computer games, then the clock frequency becomes more decisive.
Modern processors often have an intelligent workload distribution across the CPU cores. If the current workload can be efficiently distributed across several cores, this is exactly what is done, and all available cores are used. The individual cores then run at a lower clock frequency. However, if the use of multiple cores is not sensible or necessary, then the clock frequency of the cores used is increased.