Game is slow

Hi, I've been playing with The Sims 3 on my new computer for a while, and the many problems that I had while playing The Sims 3 on my dad's old computers, are gone on the new one. However my computer works with a OneDrive system, the The Sims 3 folder is inside my Documents folder which is inside my personal Drive folder; so because of this game files sinchronyse while I'm playing. I've noticed that because of this my game is a bit slow, especially in The Build & Buy mode and the Paint mode, even CAS has been slow even tho I have LazyDuchess Smooth Patch. I also have a mod folder, which isn't at all for downloading Store stuff, EA I swear, plz don't sue me. My mod folder now has 300 elements. Now I wonder; is there a way to stop this slowness? And if you were in a situation like mine, what did you do?