Yeah ur good. I mean unless you want to load your board with 3+ graphics cards your fine. BUUUUUT make sure that you're putting it in a slot that's x16 full. SOME slots if you use then will cause your video card to go down to 8x. However if your motherboard is a full x16 and x16 for video your fine.
The difference between 8x and 16x is not much. You might loose 4 - 6fps(if that much) and that would be it. Just use the card in the lowest pci-e slot. Unless you have a 1x slot you can get to.
Just check your owners manual to see what PCI-E lanes are shared on a particular slot, Asus is very good about notating that. I have the M4A89TD-Pro/USB3 from Asus and when I ran my Asus DX souncard in the 4X slot, my internet connection would sometimes drop. After a quick review of the manual I learned that it shared the lane with the Realtek LAN. I reseated the sound card and everything has been rosy ever since. Just a few minutes homework and you'll be sitting pretty.