Hi,
Recently bought a new system with z77 fatality professional (http://www.asrock.com/mb/Intel/Fatal1ty%20Z77%20Professional/)
It says :
2 x PCIe 3.0 x16 Slots
I bought a gigabyte 280x - http://www.gigabyte.com/products/product-page.aspx?pid=4793#ov
a Corsair 750 watts PSU.
GPU-z keeps...