I have two 8mb memory cards installed in my Inspiron 3647 pc, but only the Dimm1 slot says 8.1920mb. The other slot - Dimm2 reads 4.0960mb. Does anyone know why the Dimm2 is only showing 1/2 the available memory? Total available memory is only 12mb. It should be around 16mb, right?? I read that Windows 7 sets aside a certain amount of memory, but 4mb?? Seriously??