What are cores - laptop?

And does that play a major role?

For example, if an i7-6500u has 2.5 GHz with 2 learning, what would be the difference between 2 or 4 cores?

Processor core

The central part of an arithmetic unit or a microprocessor is referred to as the processor core or also the computing core. Many modern processors have multiple cores.

Source: https://de.wikipedia.org/...zessorkern

Processor cores are there to execute arithmetic commands, so yes 4 is better than 2.

It is not exactly defined what a core is.

But roughly, it's a unit of account. A core is a largely independent processor. It can perform a calculation independently of the other cores.
But often the kernels share a certain cache or something like that, so you can mostly discuss how many kernels there really are.

But, the i7-6500u has 2 cores and 4 threads. It's relatively slow, even though it's called i7.
The i7 in my 8 year old mid-range laptop is faster https://cpu.userbenchmark.com/...6930vs2730
But it also uses around 3 times as much electricity.

That means as much as 2.5 x4 and the other 2.5x2 so once you've mastered one thing, you should understand it.

These are processor cores.

Can you imagine workers, the more workers you have, the more work they create. There are a few other factors that matter, of course, but this is how you can imagine it.