The Sims 2 Problems

[btoast777]

Ok, so I own The Sims 2 with the Nightlife, Open for Business, Seasons, and Bon Voyage expansion packs installed. I play on all high settings (but without AA enabled) at 1024x764. I usually get 55-70 fps on a small-medium size house. However, after every expansion pack from Seasons on, all of the Sims' animations are really choppy and look silly compared to the smooth camera rotations and such. If I lower the graphic settings, I get the same result, too.

I have a Dell Dimension E521 with an AMD Athlon 64 X2 3800+ processor, 2GB of RAM, and an ATI Radeon X1300 Pro with Windows Vista Home Premium installed. This problem has occured when I had XP as well. So, is there any way to fix this problem?

A little side-note: When I install Seasons and Bon Voyage, the graphic settings all revert down to low on everything and I have to manually put them back on high, which still plays excellently. So, are there any "hidden" graphic settings like in config files and such that could have been reverted?

Thanks