Whats the difference between a mini motherboard and normal motherboard?

[impala123]

Pretty much what it says above, I have a case with dimensions:

450mm x 190mm x 477mm (Approx H x W x D)

And I was wondering what would be the difference between the mini and normal sized motherboards because the mini seems to be a lot cheaper?

Thanks,

 

[Azrael47]

the clues in the name really. the mini or mATX boards are alot smaller than regular ATX boards. However even though this may be ideal to someone it lacks some of the features an ATX board will include as standard, such as SLi/Xfire possibility, more memory and more headers for USB connectors or fan headers. To sum it up the smaller board is cheaper because it has less features.