Say I'm using a secondary hard drive on one computer build and I just built another computer with different motherboard, different CPU, and same OS. Can I move my secondary hard drive from my old PC to my new one without having to wipe all the data on it?
Yes you can
Practically, its a matter of just popping it into the new drive, putting it below the system drive in boot order as necessary, and just running it. In your scenario, it should be automatic.