Some differences are Max Memory supported, Dual or Triple Channel Memory,
Number of PCI Express lanes (for video cards), whether they are PCIE 2.0 x16 or 1.0,
# of USB ports, USB 2.0 or 3.0
Onboard Sound, and the corresponding audio outputs (optical, rca, ect.)
these are the main differences in price of motherboards that have the same socket and chipset.