What is System Cache?

Question

If I select this as an option when cleaning my macbook...What will I be getting rid of ? and is it safe?...( I will be using a software called onyx, if that matters)...Thanks guys..

Answer 1

What System Cache does is it collects frequently accessed data into a easily retrievable location so it does not have to retrieve the same repeatedly which impedes performance

Because the actual copy is somewhere else on your harddisk clearing system cache does not affect your system in a harmful irreversible manner