By the looks of it, it's not only the graphics card. The computer doesn't meet the minimum or recommended specs for the game.
With trying to play the game on less than recommended specs, it's over-stressing the computer and could lead damaging it.
What we recommend.Here’s what we recommend as a baseline for running the games well:
- Windows 7 (or newer) or Mac with OS/X 10.9 (or newer).
- 2.5 GHz processor or faster from either AMD or Intel.
- Gaming graphics card (such as an AMD R7 series or an nVidia GTX series) with at least 1 GB video memory. Look for a card with GDDR5 memory.
- 8 GB system memory.
- For laptops - a cooling mat (even if the laptop will be used on a desk).
Why we recommend these specs.When someone asks for recommendations for a computer, we try our best to find the best computer within the person's budget. We look at it as if we were buying the computer ourselves, balanced with what the person wants from the system. Would we play Sims with this and would it run smoothly no matter the settings? We try to aim for a better gaming experience overall: meaning less crashing, lag, slow loading and other headaches.
If you'd like to read more, please see the link below:
Buying a Computer For The Sims 3 & The Sims 4
http://www.carls-sims-4-guide.com/forum/index.php?topic=21609.msg387974#msg387974