Z97X Gaming 7 motherboard has:
1 x M.2 PCIe connector
(Socket 3, M key, type 2242/2260/2280 SATA & PCIe SSD support)
A drive that is 22mm wide and 80mm long would be listed as being a 2280 (22mm x 80mm). Common lengths for M.2 drives and mounting right now are 30mm (2230), 42mm (2242), 60mm (2260), 80mm (2280), and 110mm (22110).
The Samsung SM951 M.2
Part #. MZHPV256HDGL-00000. Capacity. 256GB. Interface. M.2 (M). Cache. 512MB. Form Factor. M.2-2280.
On the motherboard there are three length adjustment holes for the M.2 SSD. Select the proper hole for the M.2 SSD to be installed and refasten the screw and nut.