The old computer with the massive family 30+ was a VERY long time ago (about 4 computers ago) and was primitive by today's standards. At the time I only had a multi-pac (Sims 3, Late Night, High-End Loft Stuff) and University and was playing in Bridgeport. I added World Adventures and Generations on the second last, very cheap, computer (had an accident with it so it didn't last long). Recently I added Pets to my Lenovo Ideapad (purchased new for $350 about 3 years ago) just before it started falling apart (didn't have much time to play but it seemed okay though I noticed a bit of lag as expected) and now the New HP.
It's a new computer and I haven't played many worlds yet. I've only played two worlds, Ebony Strand (as mentioned above) and Pala (my own, very sparse, world) that is under construction. I play for a bit, build some lots, then save them and add them through CAW. It is so sparse right now, that I really don't like playing it and don't very often. I know Pets is heavy, but it didn't lag on the Lenovo as poorly.
Lenovo Ideapad 110-15AST
AMD A9-9400 RADEON R5, 5 COMPUTER CORES 2C+3G 2.4 GHz
8 GB RAM
891 GB Hard Drive