Jessica recently started looking to upgrade her computer and has decided that she wants to use her current motherboard and purchase new RAM for her computer. She has done all the research and has determined that her motherboard can hold 16GB of RAM and has four slots. She has two DDR3 DIMM modules that are labeled 1600 MHz. When she goes to the website to purchase them, she does not find 1600 MHz modules, only PC ratings for modules. What RAM should Jessica purchase so that she can use a quad channel on her motherboard?