Overclocking
We used ATITool to search for the maximum core and memory clocks, we then verified that the clocks were stable by running our benchmarking suite and looking for visual errors or crashes.
The final overclocks of our card are 766 MHz Core (23 % overclock, 42 % over NVIDIA reference 8600 GT) and 1015 MHz Memory (13 % overclock, 45 % over reference).
These overclocks are really impressive, first you get an already overclocked card out of the box and then you can even overclock it quite a bit more. At our overclocked speeds, the card had absolutely no problems beating the 8600 GTS in most benchmarks.
The Zalman cooler works great too. It keeps the card temperatures at acceptable levels, even when highly overclocked.