One thing you should keep in mind that the overclock settings also influence the DSP. I found out this can have great impact on using the camera/video applications.

I used used o overclock at 850 MHz using the ulv settings. But after a while i noticed strange things happening when taking pictures or video.

I went back to only 700 Mhz with higher voltages. The camera/video problems are gone now. I can probably optimize some more, but did not have time to do so yet.

So take care. Camear applications seems to be a good test case (e.g. take pictures, switch to video mode or other non-default camera modes)