Differences Between SATA I, SATA II and SATA III

Yes, SATA is compatible in both directions You can use an older HDD on a new SATA controller and you can use a new SSD on an old SATA

If you want to use SATA hard drive using the SATA port without using the onboard controllerPCI Storage controller ,an optional part is

sata slot SATA ports can be accessed in most cases on the bottom right of the motherboard Though, if you PM me the SN that is located behind the system,

sata m2 slot SATA Connectors · SATA Data Connectors A SATA data connector has 7 horizontal pins, four pins arranged in two pairs for data and 3 ground pins One end (the end