Re: 169.04 BUG: The 7 series multi core bug still exsists.
I have a 7950GT on a Core 2 Duo and have used every 100 series driver. I've run a good amount of 3D applications (including Compiz) without seeing a lockup.
Now, the "black flash" is sometimes due to the switching between 2D and 3D clockspeeds. Sometimes you'll see it, other times you won't. I'm pretty sure it's intended to do that.
I'm positive you are seeing the clockspeed change because when you use Compiz you are using the 3D engine of the card, and when it needs more power the card will jump from 2D to 3D speeds -- causing a "black flash".