If you are upgrading to a new computer, simply install PCSX2 on the new machine, run it once to generate the default folders, and then paste your old memcards and sstates folders over the newly created ones, choosing "Replace Files" if prompted. Importing 100% Completion Saves (GameFAQs)
For advanced users, you can specify a custom configuration path when launching PCSX2 from the command line using the --cfgpath= parameter: pcsx2 save game location
This will create a dedicated virtual memory card for each game, making it easier to backup specific games without managing one massive card file. If you are upgrading to a new computer,
Each save state file follows a specific naming pattern based on the game's unique CRC (Cyclic Redundancy Check) number: pcsx2 save game location