There is no compatibility issue, all PCIe standards are backwards compatible. meaning you cold run a PCIe 3.0 card on a PCIe 1.0 slot. The card will just run at the speed of the slot. I'm running a card that is PCIe 2.1 in a PCIe 1.1 slot in my old computer and it runs perfect, it just doesn't have the full speed it would if it had a matched slot. My current computer (in my sig) has a 3.0 card in a 2.0 slot, no issues, full speed for all intents and purposes.