The Sims 4 - Massive Action/Input/Simulation Lag

@_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.