With each successive board (and chipset/processor) generation that has appeared, the number of incompatibility issues has increased. Whether this is PCIe compatibility, UEFI (vs. Legacy) compatibility, etc., the issues continue to mount. While I cannot say for sure, I would bet that the "recent" graphics cards are increasingly incompatible with this board.
Not what you wanted to hear, but reality nonetheless...
This message was posted on behalf of Intel Corporation
Thank you very much to N. Scott Pearson for the information provided on the previous post.
In order to find out how the 3-way SLI works on a board, the best thing to do in that case will be to get in contact directly with Nvidia, which is the manufacturer of that product.
Nvidia’s phone support: 1 800-797-6530
Nvidia’s support site: http://www.nvidia.com/page/support.html
Any questions, please let me know.