This is an issue which has plagued me for years, across OS installs, and game versions.

The problem, is that during gameplay, I get these rather odd freezes, and they're very common. The game world will halt, with all sims and game logic freezing in place, for several seconds. Then the game will return to normal, and continue just fine for the next few seconds. Only for the freeze to happen again. It's unplayable, and when time is sped up, the time between the freezes shortens greatly. If I have the game on 3x speed, the freezes are every other second during normal gameplay.

As for my specs, they aren't the issue. I'll lay them out here:

OS - Windows 10
CPU - Intel i7 6700k @ 4.5Ghz
GPU - AMD Vega 56
RAM - 32GB DDR4 @ 3000Mhz

The Sims 3 is installed on an NVME drive, as is the Electronic Arts folder (in My Documents).

I've had the exact same issue on my previous PC, which was:

OS - Windows 7 Ultimate
CPU - AMD Phenom II x4 965
GPU - AMD Radeon HD 7850
RAM - 16GB DDR3 @ 1333Mhz

Things I've tried:

Clean install with zero mods, only every expansion and store world installed
Install Nraas Overwatch & ErrorTrap
Install SmoothPatch by LazyDuchess
Install Shader Tweaks by LazyDuchess
Install Ellacharmed's fixed worlds
Use "The Sims 3 GPU Add-on Support" to add support for my Vega 56 GPU
Modify sims3.ini to increase memory usage
Modify sims3.ini to prevent preloading
Modify GraphicsRules.sgr so High, Med & Low CPU levels are set to 3
Modify GraphicsRules.sgr so 4GB of texture memory is used
Limit the FPS to 60
Assign TS3W.exe to 2 cores
Set TS3W.exe's priority to high
Disable Story Progression, Memories, Store & Online features

The weird part, is that everyone says Overwatch & ErrorTrap stop this exact sort of behaviour. But it made the problem worse, with the freezes happening every second with those two mods installed.

I'm at my wits end with this game. I'd love to actually play it, but it has been nothing but a mess. Any ideas on what I can try?

When you say Overwatch and ErrorTrap makes it worse is so funny, sorry, but it's because I had that issue too and blamed those mods...particularly ErrorTrap. I can't say for sure but what my issue was when having that problem means one or two of two things...or more since I'm still learning about troubleshooting TS3 based on in-game misfires.

1. There is a Sim or Sims, human and/or animal, stuck somewhere in the world in an unroutable area. Even if you reset the world, this will keep happening over and over again until you find and correct this issue from starting and repeating in a loop.

2. There is a broken object or objects in the world that a Sim or Sims keep trying to use and gets stuck in a loop. This can be doors, the mini-fridge from UL, etc.

In my game those misfires causes lag, error code 12 or crashing to desktop. Once those issues are resolved, then it disappears and the game runs as intended. Provided it's not mod-related or computer related or something. What helps me a lot in trying to pinpoint what is wrong in the world is by using NRass Tagger and taking a look at all the Sims in the neighborhood and what they are doing. If I see something off, then I take a closer look to see if I found the problem or not. Be careful using MoveObjectsOn cheat or downloading lots that use it without play testing for routing issues. Make sure all the lots that come in-game, the ones you create and the ones you download are free of routing issues as well.

Sometimes placing a sign in the corner Sims can somehow get through and then get stuck. Pay attention to where seats and tables are and makes sure there is ample space for Sims to move about. Small cramped spaces and a lot of Sim traffic is just asking for trouble. There are a lot of reasons why your game may be lagging, stuttering, intermittently freezing. Also, my speculation about why ErrorTrap makes the situation worse is because it's taking up CPU resources which The Sims 3 is mostly CPU-intensive, thus a clash fighting over the CPU, resulting in poor performance when something in TS3 gets stuck in a loop and the game keeps trying to unsuccessfully map out a course. Personally, I don't use ET for this reason because I know TS3 runs into hiccups every now and then and ET makes it so much worse from my experience.

Right, so, there must be a lot of mis-information. I was following this guide, which says to adjust all those settings: https://steamcommunity.com/sharedfi.../?id=1131162350

Wouldn't be surprised if it turns out to have a lot of misinfo, as I've just done a clean install, and done only a couple things.

1 - Add my graphics card info to GraphicsRules.sgr and GraphicsCards.sgr.
2 - Set CPU levels to 4 in GraphicsRules.sgr
3 - Installed Lazy Duchess' Smooth Patch

My testing environment was to start a new game in Hidden Springs. Create a male character, move them into one of the houses, then have them go fish. Without fail, I'd get horrible freezes that lasted for several seconds, every couple seconds on triple speed. These are all completely new, fresh saves, with nothing else having been done.

Now after just doing the above three steps, no long freezes. There are the hiccups, but those are standard with Sims 3?

Core parking is already disabled, and here's my current DeviceConfig.log: https://pastebin.com/WtWHvhWe

The thing is, this is in all neighbourhoods on stock vanilla worlds, on a fresh save. All the content is vanilla, yet installing those two mods made the freezes occur even more often, where I was spending 3/4s of the time frozen than not. I'm going to give ErrorTrap and Overwatch another go, after doing only the barest tweaks as advised by Nitromon. The game is stuttery, but the freezes didn't occur immediately upon a fresh, un-modded save.

Thanks for the detailed response, I appreciate it.

I went with that Steam guide, as it seemed to have all the tweaks in it. Shame that it turned out to have a lot of jargon in it. The memory tweaks in particular reminded me of something similar for Fallout New Vegas; you actually have to make a similar tweak to the .ini files, so that the game clears the memory on fast travel and area changes, freeing up memory. Not doing so causes issues not unlike what I've been having; freezes that last for a handful of seconds.

Alas, turns out to be faulty.

The RAMDisk suggestion is a good shout. I remember trying that ages ago, and I cannot remember how that worked out. Worth a shot. The main thing that will be a barrier, I think, is if the game's vanilla packages are compressed. A glaring problem with these older open world games, is they use very inefficient (and often single threaded) compression algorithms. A common one is Deflate, which is what pre-Fallout 4 and Skyrim Special Edition Bethesda games used. The solution to stutter when moving about the game world, if you have an SSD? Decompress the archives, so the game isn't having to essentially pause while assets are being streamed in. Fallout 4 And Skyirm SE use LZ4, which is about as fast as it gets for archive decompression. Still many times slower than simply being decompressed though, in MB/s throughput.

Though, I do have TS3 on an NVME drive. Hmmm. This is something to explore.

I've done all the tweaking in the world on the processor, to make sure it's getting the right voltage for 4.5Ghz. It's not the newest, as I got it around 2017. But the only CPUs that have been released, which offer more performance at the same clock speed? AMD's Ryzen 5000 series and Intel's 12000 series. Before that, the benefit to upgrading would have just been more cores with less power usage.

Oh, on older middle ranged cards, MSAA would ravage them. Even much later cards, such as the HD 7870, wouldn't be able to handle MSAA worth a damn. Same is true for NVidia's older cards, unless it was a behemoth like the 8800GTX which could power through it. Your tutorial for adding my GPU to GraphicsRules is what I followed this time around, actually. Did the trick just fine. And strangely, MSAA does work for me. My framerate is at a constant 60, though MSAA at max is using around 40% of my Vega 56.

ANYWAY

I did a bit more experimenting, and I found something interesting. If I have ErrorWatch and OverTrap installed, along with Ellecharmed's fixed worlds? I get the freezes. But if I revert back to vanilla's, while still having ErrorWatch and OverTrap? No freezes. I think I had a double whammy before, where I did those suspect Sims 3 ini tweaks, along with running the fixed worlds, as everyone seemed to recommend them.

This is typical. I always replaced the worlds with the "fixed" ones, since it seemed like a no-brainer, even years ago. What are your thoughts on them?

Edit: Tried out using the RAMDisk, by creating a 23GB one with the OSFMount software. Renamed my Sims 3 install folder, copied it to the RAMDisk, renamed it back, then created a junction to it on my NVME drive. No noticeable performance improvement. Game took just as long to load, and still stuttered as usual.

Unfortunate, really.