Thats the same question that I've been asking about the hmc 150.
And this could also be the start of a very long thread .
But I hope someone can shed some light.
Try using Cine-V. Cine-D is noisier. And no, I don't believe they are different, they come off a production line with all the same parts and construction.
Try resetting the camera back to defaults....usually when one complains about noise, it is because the camera was adjusted way out of spec (the adjustability is a good thing, but can get you into trouble).
Return the settings to default and then things usually look better....really