In most places in the BIOS you will find the XMP option in the "tweaking" area of most new motherboards.
Simply enter the BIOS, go to the tab that has the XMP option and choose XMP. Most likely with 1600 RAM you will only have one option, some ram have more than one.
The nice thing is that is all you have to do, no extra tweaks at all. Just save the BIOS changes and reboot and BOOM you are running at 1600MHz