My Sims 3 shadows are very pixelated

Commented on the shadows by PM. I do see what you mean now (didn't at first because I was focusing my eyes on the big tree and not the grass or the smaller ones and the shrubbery) but still as I explained there is really only so much that can be expected out of an integrated video chip no matter how good it is. And even on stronger, dedicated cards carrying their own weight, the game can only use up to 800 MB of video memory, so some of this (not on every scene) can be expected for most of us. Also the way and angles at which light affects objects, even "natural" sunlight, were never entirely predicable. You can experiment with different settings on Game Options and your card itself, but likely there will only be so much improvement that can be made.

You don't have to keep the numeric fps display on. If things are staying locked in at or below 60, then all is good and you can always switch it on/off mid-game if you want to check as long as you remember to not close out (X) RTSS entirely. I keep mine on but pretty small and in an unobtrusive corner of the screen so I can feel safe knowing that RTSS is doing what it is supposed to do.

The point of this exercise was that graphics cards, usually the stronger dedicated ones but yours would be capable of doing this as well, can produce frames per second (fps) at a far higher rate than your monitor/screen can interpret. The excess over the refresh rate of your monitor would be the equivalent of digital noise, do not add to the quality at all, and can cause your system to work too hard for no purpose. Excess fps can cause graphics glitches, screen tears (lines dividing the screen into disjointed portions), lag, crashes, and can ultimately burn out or otherwise damage your system.

The human eye cannot "see" frame rates over a certain rate. But there is, for many of us, an impossible to describe exactly quality difference between let's say 30 and 60 fps or higher for those who have a monitor that runs at higher refresh rates as some do. At fps below 30, the lower quality will be more obvious and scenes will take much longer to render and come into focus as things recover from each camera move or as objects move across the screen. Most of us see this anyway on very busy, fussy lots like the WA tombs. The other place where this becomes important is with first person action and shooter games where every pixel and millisecond count towards your reaction time and success in accomplishing something. Sims games aren't like that, those waffles were going to burn and your sim was going to be late for work/school no matter how quickly you reacted to on-screen information.  🙂

Wow, thank you so much!! I really couldn't make it without your help and help of @puzzlezaddict! I can finally play Sims 3 without any problems :D. This case is officialy solved 🙂

Thank you for explaining of how framerates works! It's really interesting.