The Sims 4 - Massive Action/Input/Simulation Lag

@_artt1e  Among the many things you tried, did you ever move your entire Sims 4 folder out of Documents\Electronic Arts and let the game generate a new one, specifically without adding any content back in?  If not, please do so now.  Without any of your existing content, start a new save and let me know how it runs.

If you still see lag, please run a dxdiag and attach it to a post.

https://help.ea.com/en-us/help/pc/how-to-gather-dxdiag-information/

Yes, I did generate a new Sims 4 folder. It was one of the last 'fixes' I attempted, but aside from the game running a little bit smoother, that specific lag was still very much prominent in all different speeds. Attached the DxDiag text. 🙂

@_artt1e  Some of the errors in your dxdiag have to do with Twitch.  Are you running it or anything else in the background while you play?  Some apps can slow down the system even when there's no reason the hardware can't handle the overall load.  So please try playing immediately after you restart your computer, without opening any other apps.  Please also disable Origin in-game: hover over your username, select Application Settings, then the Origin in-game header, and disable the option at the top.

If that doesn't help, please try playing in a clean boot.

https://www.windowscentral.com/how-clean-boot-windows-10

When you reboot, please also go through the Task Manager's background processes list and shut down anything that doesn't absolutely need to be running.  There are plenty of apps, everything from MSI Afterburner to lighting software, that don't get disabled in a clean boot, and you'll need to shut down all of them.

Apologies for the late reply.

I did everything, step-by-step, as you suggested, and I’ve been fiddling with the game for the majority of the evening. Starting the game after a clean boot + using Task Manager to close background apps/programs, the game seems to be running smoother in terms of FPS. There were two times in my playtime where there would be these odd lag spikes that would only be fixed by pausing and unpausing the in-game time. 

In terms of the weird, annoying input lag, it’s still not fixed, unfortunately, but it’s not as bad. It’s still there, and very much noticeable especially when in 2x and 3x speed. There are some minor tasks like getting mail or cleaning that don’t experience the lag, which I think is an improvement because before all this every action and order my Sims did was plagued with the lag. Even my Sims eating and interacting, sometimes, goes by smoothly without any lag, but actions like going to the toilet and then washing their hands have the lag in-between each action and right before they do the action—after walking in front of the toilet/sink, they just stand there, thinking, before the game finally processes that they need to do an action. 

I would also like to quickly add that my Sims tend to freeze up when they’re in the middle of doing something when on 2x and 3x speed. The only way to unfreeze them is to pause the game, then go back to normal speed, or use the ‘Reset Object (Debug)’ option because sometimes even after pausing to give the game time to catch up the Sims will just stand frozen (no animations whatsoever, sometimes if they have an object in their hands it’ll just phase through the hand as if they‘re not holding anything). 

@_artt1e  I'm curious whether there's something else going on with your computer that wouldn't show up in a dxdiag.  Would you be interested in some hardware monitoring?  If so, download hwinfo from here:

https://www.hwinfo.com/download/

You don't need to install anything if you don't want to; just choose the Portable version, unzip it, and launch it from Downloads or wherever you want.  (If you would like to install, be sure to click the green button, not the orange one.)  Restart your computer, and don't open any other apps.  Launch hwinfo, choose "sensors only," and click the icon that's a sheet of paper with a + sign to start logging.  Save the file to your desktop for easy access later.

Wait five minutes, then launch Sims 4 and play for at least 20 minutes, long enough to see some serious lag.  Click the same button to end logging.  Then upload the log to a third-party free filehosting site and link it here.  Please leave it in .csv format, or if you use OneDrive to share, please compress it in .zip format instead.

And just to clarify, please test again in a clean Sims 4 folder, to keep the complicating factors to a minimum.

Link to the logs here! First one is with my usual save file, second one is with a new folder. 

https://drive.google.com/file/d/1cQ22HuSVqOAbrkX8C_Hxpbif_hzI0l6v/view?usp=sharing 

https://drive.google.com/file/d/1NzKUf8ZnY2ALp4SRWtuwPUsFamWQsGx3/view?usp=sharing

@_artt1e  The temperatures in your system look fine, and aside from one glaring detail (more below), there doesn't seem to be a reason why your computer would be running Sims 4 poorly.  How did the game run with the new save, as opposed to the old save?  On the one hand, it looks like your system was running a bit faster in the second log: effective clock speed was a bit higher on all CPU cores, and the components were a bit hotter overall, which would be expected with an increased workload.

Even more starkly, the GPU clock speed in the first test dropped repeatedly and significantly, while it mostly held steady in the second test. You can see the contrast between the two here, with the results from the first hwinfo log in green and the second in red:

(I trimmed down the first log to get an equivalent comparison with the second.)  The graphics card itself isn't overheating though, and presumably you were playing the whole time, or close enough, so there's no reason the graphics card's load should have dropped enough to account for the downclock.  The GPU core load was higher in the second test to go with the higher workload of the other components, but even when the loads were relatively even, the clock speeds were not.

One thing I did notice is that the input voltage of the card's PCIe slot dropped dramatically, actually more in the second test than in the first:

The expected voltage is 12V, and anything below about 11.9 could potentially be a problem for performance.  The significantly lower readings in the second test in particular suggest there might be an issue with your power supply, or perhaps with the connections between the PSU and the various components.

So please check all the PSU connections, both on the other components and on the PSU itself if it's semi- or fully modular.  Please also let me know the manufacturer, wattage, and rating of the power supply, e.g. Corsair 750W 80+ Gold.  The information will be printed on the side of the unit, although you may have to open the back of the case to see it.

And let me know what motherboard you have as well; the model should show somewhere obvious on the board.