FPS (frame rate per second),

This can be handy to see if you maybe can set your settings lower to have a flooting view.

It can occur that your sim seems to 'freeze' for some time

In Sims3 there is a cheat - fsps on - that can tell you how fast your view changes. You will see on right top a number when you use this cheat. If it's less then 8 you really need to set your settings lower
A good flooting view minimal needs 15 fps (the higher the better)

Watch for the high detail lots. Try out some settings, some only will work after restarting your game.