I'm still not sure how my game ran back in 2012 when I originally got it, but I do recall being incredibly patient about the many (many, many) loading screens, which seemed to take several minutes per lot. That said, I don't remember lag of any kind when actually playing lots themselves, and the situation seems roughly switched now-- my lots load fairly quickly, but run horribly once I'm there. I've gotten a lot of funky comments about frame rate from computer friends...
But that's just a justification to post a full description of how exactly my game loads with nothing obstructing it. I've gone through all the compatibility-whatevers, I've loaded the things and modded the things and set DEP to How It's Supposed To Be, and I even restarted my computer and went through Task Manager to remove all the shit (Skype) that keeps opening itself (Skype) to run in the background (Skype) and take up all my disc space (just signed out of Skype, because unfortunately there is no option to just remove the darn thing because I'm running Win10.) I have ~5 GBs of CC (which I am working on, but have Compressed and Bulk Renamed already.)
I set a timer and double-clicked the start icon. It was time to wait, taking notes along the way.
01:00. No change. Starting to wonder if I clicked the icon, but not willing to click it again just in case.
03:30. Loud whirring noises emanating from computer.
03:45. Blue screen appears. The right size, but absolutely nothing displayed.
4:00. Opening video launches. I say sul sul! exactly in time with the tiny plumbbob and watch the whole thing play through.
4:49. The loading screen appears-- sort of. It's glitched and frozen and odd-looking, and the whole thing is kind of blurry. Clearly not the normal one.
5:23. The fake loading screen melts into the real loading screen, which immediately begins playing
elevator music. The bar refuses to move, and no loading text appears below it.
10:00. The screen still isn't loading. I question my sanity, but don't move from my computer. I need to be able to catch everything; this is no time for snacks.
15:32. Getting kind of hungry, though.
18:00. EVERYTHING STARTS LOADING AT ONCE. Text is flying, bars are moving, I almost fall off my bed in shock.
18:26. And it freezes. Pinwheel, stuck loading text, all of that. The game Over-Wax[es] Banisters for quite a while, stuck at 4/7ths of the bar loaded.
20:02. The game gets moving again, but gets stuck at 5/7ths. Come on. Come on, baby. I've been sitting here doing nothing for twenty minutes.
20:10. And we have another pinwheel.
21:00. 6/7ths. And everything is speeding along again, until--
21:20. DONE! Main neighborhood screen. And I've had 60 minute wait times with tabs open in the background, so I'm not that upset.
Still-- is 20 minutes normal? I'm pretty happy to get down to there, but I've heard people say their game loads in seconds. I'd assume that's on some kind of advanced gaming PC, though...