They have different working frequencies and hardware support including amount of memory which can be installed, hard drive types (IDE, EIDE, SATA, SCSI...). Also they they have different kinds of sockets (place where you the CPU is). Thus, they are usually not compatible with each other.
The difference is that GeForce is a chipset for graphic cards and nForce2 is a chipset for motherboards ;-)
Difference is only in the architecture,but working principle is same,
Laptops do not typically have motherboards into which perpendicular daughter boards can be plugged at will. A laptop's circuits are usually divided into 2 or 3 main boards with some optional functions on mezzanine boards so everything lays flat and takes as little space as possible.
Discreet refers to a separate GPU chipset, example: ati/nvidia, while UMA is the Intel integrated graphics controller.
Nvidia is the name of the company, which manufactures motherboards named nForce and graphics card named GeForce. They are 2 different pieces of hardware.
Desktop motherboards all conform to one of several standard form factors, such as ATX, microATX, NLX, or mini-ITX. The motherboards in laptops, however, all have different sizes and are custom fitted for the laptop chassis. Laptop motherboards do not typically provide the number of expansion slots found in desktop motherboards.
10 motherboards
If you mean "how many models of motherboards" - thousands. If you mean "how many pieces of motherboards" - probably billions.
For the most part it's size, and AT is very old computer wise. See here for more detail: http://www.devhardware.com/forums/motherboards-32/at-vs-atx-179846.html
See the Related Link below for pictures of motherboards.
All Intel chipsets and motherboards support crossfire.
Ports are not used as a reference to TCP/IP and UDP logical connections.Now, the serial and parallel ports are no longer provided in the manufacture of most motherboards,and has been largely replaced by USB technology