So recently I noticed that when my camera view is near the street/sidewalk the game just lags.When I move it down to the opposite lot it works smoothly. When I move further into the lot it , away from the street, it also stops and everything works just fine. It's not the building's fault, because it happened when there were many objects, and it happens now when my house has only a few object in every room. I don't know what may be the cause, it's not the sims or any objects, at least I don't think it's the objects because there's no cc objects outside.

* Does the lagging happen more frequently or is worse when NPCs/townies/strays are visiting?
Some NPCs/strays can cause moments of lagging. I've noticed lag spikes when sims or strays are walking onto the lot, special NPCs such as the wolf "leader of the pack" arrive, or anything the game needs to load in for the first time. If sims are changing skin overlays (sunburn/freeze/occult transformation, etc.) this can sometimes go unnoticed on the sim in question, but be noticed as lag if your camera is elsewhere, and can be easy to mistake for something else. Moving the camera while in live mode (not paused) can sometimes also cause the camera to lag a bit.
(The lagging depends on your computer - I've had anything from a barely noticeable second or two, to several minutes, depending on computer specs).

* Do you have any mods to reduce, increase or alter the NPC/townie/stray walkby rate? Or have you enabled the cheat to increase visitors (often part of mods that increase the amount of sims on lots)? Or the mod that adds car drive-bys? Or anything similar?

* Do you use default replacement clothing or hair that are high poly (and/or have large/many textures)?
Could be townies generating with these.

* Is it a large lot (4x4 or larger)?
Large lots tend to be laggier than smaller lots, regardless of CC or not.

i think the lot isn't lagging when sims aren't on the lot, but then why would it lag only in one place? it never happened before, i didn't download any new games or big files so it's not my pc's fault.

* i don't

* no, it happens when no sim is wearing any cc

* no, it's a small lot, i don't exactly remember but i think it's 2x2, but it didn't happen before on bigger lots

after i noticed the lag i made a new family, everything worked fine when they were living in an apartment but then i moved them into a house on a 2x2 lot and suddenly it started lagging just near the street/ the entrance of the house. The house was almost empty so it wasn't caused by the amount of objects/cc

then i made a second family, it was just one sim. it was fine for a while but then it just started lagging for no reason. i have no idea what's going on

update: so i noticed it only happens when the sims are inside the house, if they're outside it doesn't lag :DDD i have no idea how to fix this

* Have you noticed any particular time of day (ingame) the lag happens? Could be linked to a particular event, or some other thing that happens at soesific times of day.

* How long is the lag (roughly) every time (barely noticeable, seconds, minutes...?), and is your game paused/unpaused/at higher speed while it lags?

* Do you have shadows (+ sim shadows), reflections, and shaders enabled? (could be your game is reacting to sim shadows or sun shadows)

It lags all the time, just in one area of every lot

I do have shadows and reflections but i had them before and it didn't use to happen

I actually think it might be lagging when sims come into the camera I made a one-sim family then added 2 more sims via tombstone of l and d and when they entered the house it started to lag even worse.

Do an experiment for us.
Drag your Documents/ EAGames/ The Sims 2 folder to the desktop.

Run the game so that it creates a fresh set of folders, and test a fresh neighbourhood (or one of the Maxis premade ones).

Do you have the same problem then?

(You can delete that folder and put your old Sims 2 folder back after you've tested this).

i messed around with grm and it actually stopped lagging now, thanks for trying tho! i'll try it out if it starts lagging again

Oh good, glad you got it sorted! Well done.