On my computer iv noticed that in the BIOS XMP is disabled for my memory. Why would this be disabled by default? Is it better for me to leave it disabled or should i turn it on? im not sure

Motherboard- Gigabyte p55m-ud2
RAM- Corsair Dominator

Thanks

If anyone reads this and wants to know what happened i enabled XMP and used profile1 and it changed the following settings. it changed the frequency on my RAM from 1333mhz to 1600mhz and changed the latencys from 9-9-9-24 to 8-8-8-24.
It disabled turbo boost on my core i5 and changed the fsb speed from 133mhz to 166mhz but changed the multplier from 20x to 16x. I ended up just disabling it again