whats the difference between
https://www.amazon.com/Intel-I7-6700-FC-LGA14C-Processor-BX80662I76700/dp/B0136JONG8/ref=sr_1_2?ie=UTF8&qid=1473279568&sr=8-2&keywords=core+intel+i7
and
https://www.amazon.com/Intel-Unlocked-Skylake-Processor-BX80662I76700K/dp/B012M8LXQW/ref=sr_1_1?ie=UTF8&qid=1473279568&sr=8-1&keywords=core+intel+i7
https://www.amazon.com/Intel-I7-6700-FC-LGA14C-Processor-BX80662I76700/dp/B0136JONG8/ref=sr_1_2?ie=UTF8&qid=1473279568&sr=8-2&keywords=core+intel+i7
and
https://www.amazon.com/Intel-Unlocked-Skylake-Processor-BX80662I76700K/dp/B012M8LXQW/ref=sr_1_1?ie=UTF8&qid=1473279568&sr=8-1&keywords=core+intel+i7