I have a problem with my video. I cannot understand what is going on. I have xbox 360 slim 4gb, and monitor Samsung p2770hd. I connect my Xbox thru HDMI with 1080p resolution. Everything seems to be ok, but in a game in some moments I can see some "pixelated shadows, or black dots" I don't know how to call it.

For example Mass Effect 2 , in dialogs that effect appears at characters with whom I speak. or in some place when it probably should be a shadow on object.

In fable 2, a lot of such dots , on a decoration objects shadow. And so on.

I've tryed to manipulate with xbox settings, but it didn't help. Any ideas ?