As promised [H]ard|OCP has spent some time overclocking the ASUS GTX 660 DirectCU II card and have come back with their results.  The highest GPU clock they managed was a reported 1170MHz Boost clock in GPU Tweak but which was 1215MHz in actual in-game performance.  While that was the high speed record it did not provide the best performance as the frequency often dipped much lower because of the heat produced, [H]'s sweet spot was actually a 1100MHz Boost clock, in-game a much more steady 1152MHz though it did still dip occasionally.  They also upped the memory, but again because of the heat produced by the overclock they could not raise voltage without negative consequences.  Check the whole review here.

"We put our new ASUS GeForce GTX 660 through the ringer of overclocking and make real world gaming comparisons. If you are thinking the new GTX 660 (GK106) GPU will be a good overclocker like its bigger brother GK104, you may be in for a surprise that puts the new GTX 660 in a new light."

Here are some more Graphics Card articles from around the web:

Graphics Cards