Memory setting questions

I'm not concerned about overclocking my memory but in checking my ASUS Maximus X Hero BIOS I see that the frequency was already set to below the 3600 memory. There is an option in the drop down that I can choose to set to 3600 but is that better than leaving it to default settings or should I set the AI OC Tuner to XMP? At the least I want to get out the memory what I've paid for.
I know zilch about memory settings.