You have to purchase them.Dual channel memory is the box with two rams you know ...... example : https://www.google.gr/search?q=2X4+memory+ddr3&es_sm=93&source=lnms&tbm=isch&sa=X&ei=o9VZU8yGAaSM0AWd1YCQCA&ved=0CAYQ_AUoAQ&biw=1776&bih=875#facrc=_&imgdii=_&imgrc=cLCfeieTomxrNM%253A%3BNN-pyxztipUKbM%3Bhttp%253A%252F%252Fthumbs.ebaystatic.com%252Fd%252Fw225%252Fm%252FmAd9sVaZcT0myd_kzY7XcbA.jpg%3Bhttp%253A%252F%252Fwww.ebay.com%252Fclp%252Fcrucial-240-ddr3-sdram-computer-memory%252F170083%253Fquery%253DBrand%25253ACrucial%25257CNumber%252Bof%252BPins%25253A240%25257CType%25253ADDR3%252BSDRAM%3B225%3B338