OCC has published a review on the ASUS EAH5750 Formula

CCC found 860MHz on the core and 1210MHz on the memory as the maximum clocks. I had a nice base for where to start overclocking. I began by increasing the clocks by 10MHz on the core and found that the 860MHz was the highest benchmark-stable speed. When it came down to the memory, I was able to push it an extra 20MHz.

ASUS EAH5750 Formula Review