Black Friday?

I'm having a struggle here. I wouldn't mind adding a few more packs, but I'm not sure how wise it is considering my computer specs. I love making videos, so the performance can't go too low. With about 10 packs installed, everything works pretty well, though, at least when I remember closing down most other programs running. Lately it seems like Windows itself is running quite heavy and random tasks in the background making my game lag periodically, but I think that would have happened even if I had less packs installed. Don't think those lags are game related at all. I'm actually surprised how well my low-end computer with integrated vid card performs this game (so far).

So - my question is how much lag each new pack installment would cause? I know there's no way to tell for sure before trying, but is there some sort of a general rule? I heard new forms for relations might slow down things, so I avoided IL that would have introduced a new life form.

I have all EPs except IL, + 5 GPs and 1 SP. + some CC. Getting 1 more stuff pack is probably not a big deal, but what if I grab a full bundle...? Wish I knew a bit more about how the additions affect technically.