What is the difference between these three cards his 6870 normal one iceQ and iceQ X
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161389
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161393
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161396
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161389
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161393
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161396