asus p8h61-m lx3 r2

Hello. I am using NVIDIA GTX 1050 Ti with i3 3240 on ASUS p8h61-m lx3 r2.0 motherboard which supports PCIe 3.0 but my 1050Ti is only using 2.0 at max even when am playing games. Does anybody know how to solve this I have already checked in bios but there is no option for changing PCIe gen version.