ASUS P5W DH Deluxe Help with Gbps LAN

[zcpu]

i have this motherboard and i have gigabit network , my other computers showing the speed is 1Gbps except this motherboard showing only 100 mbps

please tell me what should i do to make it 1Gbps transfer speed instead of 100 mbps

do i need to plug in both my ethernet cable to those 2 gigabit that provide by this motherboard

thanks