A:Answer The mac mini expansion for mid=2late 2012 models will fit SODIMM (small operating), PC3-12800 DDR3, unbuffered, non-parsing, 204-pin, 1600 hz. Will not work if RAM has register or buffers PLL's, ECC, Parity, or EDO RAM. Go with the specifications to your model to know. Apple icon and "About This Mac" and it will say after MAC what version to search for in apple website for upgrading RAM and instructions. My mac mini is a late 2012 and took 2 minutes to get specs and instructions, which takes 10-15m to install. Antistatic protection recommended on top of Apple instuctions. Upgrading RAM to 8 or 16 GB replacing OEM equipment best as 2 x 4 or 2 x 8 GB. If no improvement on system then you may need to upgrade your MAC.
https://support.apple.com/kb/index?q=MAC+ram+upgrade&src=globalnav_support&type=organic&page=search&locale=en_US