Will sata 2 run on sata 1?

Yes, SATA II (SATA 3 Gb/s) devices are backward compatible with SATA I (SATA 1.5 Gb/s) interfaces. This means that you can connect a SATA II hard drive or SSD to a SATA I motherboard, but the drive will operate at the lower SATA I speed. However, if you connect a SATA I drive to a SATA II interface, it will run at the SATA I speed as well.