PCI Express 2.0 x16 Slots are available on the board.
Interface of the GTX 950 is:
PCI Express 3.0 x16
Even though the card is PCIE 3.0 and your board is PCIE 2.0 , THERE IS NO LOSS IN PERFORMANCE AND IT'S 100% COMPATIBLE.
https://www.pugetsystems.com/labs/articles/Impact-of-PCI-E-Speed-on-Gaming-Performance-518/
Impact of PCI-E Speed on Gaming Performance.