Does anyone knows if a Dell 412 motherboard support Intel Core 2 Quad Q9550 processor? I have now a Intel core 2 Duo E6850 and 12GB internal memory and it works great.
The simple answer is no. As you can see here: http://www.findlaptopdriver.com/dell-0tp412-specs/
Not only does it not support a quad core. But on top of that it doesn't support your aclaimed 12gb of RAM.