the Adata 3gb 1333mhz ram clocks amazingly. You can get it up to 2000mhz, and it can run at much higher voltages too than normal ddr3 ram (1.75 or 1.9 i think) where as most ram is 1.65v.
i've currently got 6gb of Patriot Viper 1600mhz @ 9-9-9-24 and its perfect. Looks amazing, stable as anything.
This is my second build using patriot ram and both have been great. And if my last build was to go by, this ram will clock really well too!!
unfortunatly OCUK don't stock Patriot ram, but look around and you should be able to find it. Only 195 notes too, which is good for 6gb of very fast ram.