High mega pixels = worst noise performance?

So I was looking up some information, and I was reading up on the Nikon D800's 36 MP. And it was said on this video that one of the bad things about having so many MP is that noise performance suffers… Is this true?

It CAN be a problem, yes. A sensor only has limited space and cramming ever more pixels onto it means that something will have to give.

It's the pixel size that matters. The D800 has a crazy high MP figure but it also has a large full frame sensor.

In fact it does not as good in low light as the 12MP D3s (which performs incredibly well), but it still beats any crop frame camera by far, it's just a little bit behind the D3s due to the newer sensor technology.

http://www.dxomark.com/...nd3)/Nikon

So in short, at *equal sensor size* and within the same technological generation more MP mean worse low light performance. But sensor size and age of the sensor technology play just as much of a role.