I am confused

[I am bad a usernames]

Hi everyone,
I need help figuring out what exactly overclocking ranges are. Im wondering what a "mild-really good" overclock is and the specs needed to acomplish such goal, like what CPU and what kind of cooler would be good, air or watercooled. I see all this 4. whatever and i need to know what all that means.

 

[Rhezner]

what is your budget. Get a noctua nh-d14 if you want a decent overclock on air, Get a 280l if you dont care about noise and want a good overclock on water.

A good CPU is the i7 4790k for a high budget

how far you can overclock depends on the CPU