Overclocking
To find the maximum overclock of our card we used a combination of Rivatuner, ATITool's successor, AMD internal software, Furmark and our benchmarking suite.
The final overclocks of our card are 847 MHz core (6% overclock) and 1020 MHz Memory (2% overclock). These overclocks are slim, I would have expected more from watercooling. The memory overclock seems limited by the heat of the memory chips on the back side which are not cooled by the waterblock.
Using these clock frequencies we ran a quick test of Call of Duty 4 to evaluate the gains from overclocking.
The actual 3D performance gained is 2.8%.
Temperatures
While the temperatures are quite low they are not amazingly low as one would expect from watercooling.