Hello, I am using a GIGABYTE EX58-UD3R (http://www.newegg.com/Product/Product.aspx?Item=N82E16813128375) and using 2x2GB DD3 1600 Ram (http://www.newegg.com/Product/Product.aspx?Item=N82E16820211409). Currently, it shows 4GB ram installed, only 2GB usable. Is there any way to make that other 2 GB usable or will I have to purchase new ram?