i had bad luck with that batch splave, really hope you can do better!
just a heads up, seems these new batches stay cool. As in you might only do 5ghz at 1.35v but the cpu will stay cool. Thus at ln2 you can pump volts and get up to 6.8ghz with all cores like Mike
So if you get stuck at 1.35v for 5ghz it might be worth a shot on ln2 like here:
http://www.hwbot.org/forum/showpost.php?p=201555&postcount=404