Today I bought MSI GTX 760 graphics card. It is PCI-e 3.0
And, my motherboard is Asus Sabertooth Z77 which also has Pci-e 3.0.. So, I connected the card to the first PCIe slot. But, when the computer booting up, it shows "Using PCI-e gen 2"
Why is that? how to activate PCI-e 3.0 ?