It would indeed be weird if RAM use was the issue before the Main Menu; I thought you might be trying to load an overstuffed world.
Do you happen to have the Windows 10 Creator's Update? The associated issues seem to have mostly disappeared now (one year and a bit later), but maybe disabling the effects could still help you.
https://forums.thesims.com/en_US/discussion/comment/15902876#Comment_15902876
Other than that, maybe a dxdiag is in order.
https://answers.ea.com/t5/The-Sims-3/HOW-TO-DxDiag-PC-Only/m-p/1049584/thread-id/47181