do you think you would operate smoothly with audio engineering software such as Logic ProJust to clarify kschendel answer about RAM for all 21.5-inch iMacs - The late 2011, 21.5-inch iMac (and going back to the first 21.5-inch, Late 2009) is easily upgradeable by the user.
iMac 21.5-inch, 2012 model and both 2013 models are not easily upgradeable, requiring challenging disassembly to get to the slots.
The Late 2013 21.5-inch, and later, all use soldered memory - no slots at all.
The OP's mid 2014 iMac did not even have a RAM option. 8GB only.