There shouldn't be. The drivers distributed by Asus were made by nVidia, and if you use some generic Windows drivers, the nVidia drivers should replace them. So if you're having some sort of problem, maybe you should expand a little more on what the issue is.
I've been having a problem enabling the SLI on my gtx 550ti(s).
I've read on forums on this site that REALTEK drivers conflict with Nivida audio drivers.
I've updated bios, confirmed both cards are working, confirmed the mobo pci slot is working, and tried different (301.24 and 295.10) nvidia drivers.
When i install, i can tell the difference in resolution with the one card, but when i try to enable it uninstalls/doesnt recognize my video cards and doesnt enable SLI.