Your motherboard says it has "1 PCIe 3.0 x16, 1 PCIe 2.0 x16, 1 PCI 2.0 x1, 1 PCI ", which means you can put your GTX 950 into PCI express 3.0 without any performance loss. Also, PCIe 2.0 x16 will work too with 1-3% lower performance.
Yep, writings on motherboards can be confusing, there is how PCIe slots look like: (you just gotta know how it looks
😀)
http://www.hardwaresecrets.com/wp-content/uploads/190_041.jpg