how do i know if my GPU is activated to PCI-E 3.0.
im using GTX 670
You need a pcie 3.0 Motherboard. honestly it doesn't matter. You wont see any noticeable performance increase and if your card is 3.0 and mobo is only 2.0 that is perfectly fine as its backwards compatible.
You can use a free utility called GPU-Z and check if its 2.0 or 3.0 or whatever.
Hope that helps.