I have a 2nd gen Intel® Core™ i7-2600K Processor (8M Cache, up to 3.80 GHz) and need to upgrade my GPU. This CPU can handle pci-e 2.0 cards only and not 3.0. I have bought a GTX 1070 and could not make it functional due to the PCI Express Revision supported by the processor. It seems that some pci-e 3.0 video card can function on the 2.0 slot, but the CPU don't accept it? I have red that some worked, but for me it was not working and I verified with ASUS tech support and they told me it was due to the CPU PCI expansion compatibility. So, I'm wondering what would be the top 3 video cards that this CPU will be able to handle? I have a ASUS P8Z68-V Pro GEN3 for the motherboard (it can handle the pci-e 3.0 cards, the board is not the problem. Verified by ASUS). Any suggestion please? Regards