Wish I could understand German.  SimTimes pointed out the fact that german site PC Games Hardware completed a test and gathered screens for The Sims 3 running on low, medium and high settings.  Here’s an example below, check out the site for a few more samples.

LOW DETAILS

10_Sims3_Low by you.

MEDIUM DETAILS

11_Sims3_Medium by you.

HIGH DETAILS

12_Sims3_High by you.