i7-970 memory compatibility question...

Hi all
I've read on ark.intel.com the i7-970 is compatible with DDR3-800/1066; however, I've heard of people with the i7-970 who use DDR3-1600. I'm confused about what will work and what won't. :-? Can anyone help?
I've read on ark.intel.com the i7-970 is compatible with DDR3-800/1066; however, I've heard of people with the i7-970 who use DDR3-1600. I'm confused about what will work and what won't. :-? Can anyone help?