i currently have just one 1TB HDD that goes into the sata 3.0 slot on my mobo.
i want to upgrade by adding an SSD but i only have one sata 3.0 port on my mobo.
can i put the HDD in a sata 2.0 slot so i can put the SSD in the 3.0 slot? or do they both need a sata 3.0 port?
my HDD is a hitachi HDS721010DLE630 at 7200RPM
my mobo is a ASRock B75M-GL
Devices, such as your HDD or SSD, that are capable of using SATA III will still function when plugged into a SATA II port, so you can definitely use your HDD on SATA II and your SSD on the SATA III. Data transfer rates will obviously be slower on the SATA II port, but it will still work just fine.