like said before could be clever binning... other example My Corsair GTX2s are far sub par then most out here ( K I don't pump 1.75ish volts through them) but 2200cl7 is usually a no go on I7, same for AMD benching 2000CL7 is a pain in the but... same Ics world of difference, yep sometimes luck is involved...

Open your ripjawsX ( goes pretty easily ) and give us a piccie Alex plz

these are my 2133CL9-10-9-28 1.5V F317000CL9D-4GBXMD