I am also using the Intel D975XBX also; with an Intel E6300, 2GB DDR2 667, a reference 5850, and a non-reference Sapphire 5870, and this PS is serving me well (I don't have any exact usage figures, though): http://www.newegg.com/Product/Product.aspx?Item=N82E16817371026&cm_re=earthwatts-_-17-371-026-_-Product