If you're vedio card is borderline. Makesure it's set on max or properly set up in you BIOS.
Even if you have a 256...you might only have it set at 128mb

You can try running the sims in 16bit colors. It'll cure a lot of sticky situations.
Then you gatta look up what the heck antiasiling is on your vedio card options
Especailly if you have Vista.
Notice in Vista if you have it on 32 bit ....you're tool bar on the bottom of the screen has a pretty cool looking deal.
It's a little window with moving pictures/vedio and all Kind of like PIP. it'll drive the heck out of your vedio card thou.lol
By running it in 16bit it'll remove that.

It helps if you have a nice screen .lol