Could you please post the following info
- Your Computer's DxDiag
If you have, the following file: Documents\electronic arts\the sims 4\lastcrash.txt
- The following file: Documents\electronic arts\the sims 4\config.log
You can upload DxDiag and config.log directly to your post.
For any lastCrash files, either create a rar file and upload that or copy/paste the content of the file to a post inside spoiler tags (the icon next to the strike-through)
Also could you try playing in windowed mode and check on your RAM usage while you play ? How high does it go ? How much is used of your overall RAM ?