Could you possibly tell me what your in-game settings are?
I run a similar build and normally get around 30-40 fps (depending on the situation)
Also make sure High-End Mode is turned off and that will always improve performance!
You've only given us half a computer to work with. Do you have an hdd or an ssd? If you're on a standard hdd that's probably what's limiting you. Games like Black Desert have a lot of data to be read all the time.