sate slotMost desktop 2.5 drive bays are open-top, open-back and can handle any 2.5 drive, but occasionally you'll find a slot bay desned for one specific heht of drive (usuallySo a gen4 drive in the 3.0SATA slot will be limited to gen3 speeds, as will a gen3 drive in the 4.0 slot. But either will work just fine. So if you get one 3.0 drive, mht as well put it in