Unlocking CPU cores, AM3 AMD Phenom II Black 560?

My system is running really slow and I just bought this computer, put it together, the motherboard is an MSI 870-G45, I go into the BIOS and try to unlock the cores but I don't know if it's working or how to make sure it's working, how can I tell if they are unlocked? I have a program called AMD Overdrive and it says I have CPU0 and CPU1, also what is this POST? The manual says I can find out if it's unlocked or not in the POST, how do I reach this POST? Please help!!!