Hi. I have an xps m1210. I checked out the ram on crucial.com. It says that the ram compatibility is up to the DDR2 667. Is that a fact? Can I use DDR2 800 instead cause at http://www.newegg.com/Product/Product.aspx?Item=N82E16820227251 one of buyers said his laptop supports up to 667, but he used 800 at max speed?