Purchased an asrock 990fx extreme6, having a tough time selecting ram. I'm going for a single stick of 16gb 1600mhz ram, can't find anything on pcpart picker. I have the ram left over from my last desktop, 8gb/4x2gb pc3-10600, if this ram is compatible I've no need to buy any, but any ram I select on pcpart picker trips the compatibility check option. Grrr.