GB seems slower

As of late GB seems / is a little slower doing some funcutions. Where I notice it the most is when I copy a part . Which I do a lot . I play mostly Reggae so much of a song is basicaly the same. I'll make several parts on the bass and drums. Then I build up the song from there . The only parts I play more / longer on are leads and vocals. And at times I copy vocal parts too. So that's the basic idea of how I work .

At first ( when I first got this iMac ) when I copied a part , it just "snapped in" . Now there's a little delay ... maybe a second or 2 ... is this something I should be worried about ?

I do have a lot of GB projects still on my iMac. Many are finished .... I have a 4 TB drive so I figured I could be lazy and not save those to disk . Could that be my problem ? Or this there something else I should look at ?

Thanks & Peace