I would <i>guess</i> that "box" refers to retail packaging. I've never heard of it said this way, but it wouldn't surprise me.
OEM is non-retail. It's packaged for system builders like Dell, Gateway, etc. who don't care about manuals, pretty packaging, software, and so on. They just throw the parts into a complete system anyway and sell that with their own manuals, pretty packaging, software, blah, blah, blah. And they offer their own warranty, so they don't need the retail warranty.
So retail = with cables/manuals/software/warranty/etc.
OEM = just the hardware, usually just 30 day warranty at most
Just be sure that "box" isn't "white box" because that's another name for OEM. (Because the parts are stored in generic white boxes.)
<font color=blue><pre>If you don't give me accurate and complete system specs
then I can't give you an accurate and complete answer.</pre><p></font color=blue>