What's the difference between these two graphics cards? They are both the GTX 980 but they are from different brands, one has a "Zotac" before an the other a "Gigabyte"
http://www.newegg.com/Product/Product.aspx?Item=N82E16814500358&cm_re=gtx_980-_-14-500-358-_-Product
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125683&cm_re=gtx_980-_-14-125-683-_-Product
http://www.newegg.com/Product/Product.aspx?Item=N82E16814500358&cm_re=gtx_980-_-14-500-358-_-Product
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125683&cm_re=gtx_980-_-14-125-683-_-Product