Sims 3 Choppy Gameplay

Hello, I finally got the sims 3 up and running and now I'm running into some lag issues. First off, here are my PC's Specs:

CPU: Intel i7-3770k at 3.5Ghz
RAM: GSkill 1600Mhz DDR3 running at 1333Mhz 8Gb
Motherboard: ASUS p8b75-m/csm
HD: WD Green 2TB
Video Card: Nvidia GTX 570 Superclocked Edition

Basically my point is it's a pretty high end system capable of handling games like Crysis on full settings no problem. However in the sims 3 I'm getting choppy gameplay. Cars skip frames and scrolling through the map is choppy about every 3 secs.

Here's what I've tried so far:
Patched TS3W.exe to be able to use 4gb of RAM
Consolidated package files using s3pe
Removing package files
New save
Different video card (Tried a AMD Radeon HD 7870 Direct CU II)
Removing conflicting packages with Sims 3 Dashboard
Using the resetsim function as well as NRAAS Overwatch
Lowering Video settings in game to lowest settings
Overriding Sims 3 setting via Video Card driver utilities


Anybody know what could possibly be causing this choppyness/lag? It's also worth mentioning I've tried the same things on another computer with these specs:

CPU: Intel i7-2600k at 4.0Ghz
RAM: Kingston 1600Mhz DDR3 8Gb
Motherboard: Gigabyte Z68X-UD3H-B3
OS SSD: Corsair Force 3 120Gb
Sims 3 HD: Seagate 1TB USB 3.0 External
Video Card: AMD Radeon HD 7870 Direct CU II + Nvidia GTX 570 Superclocked Edition

It seems like both of these rigs should be able to handle the sims 3 without any problems. So if anybody has any idea on what could be causing this it would be greatly greatly appreciated. Thanks in advance for any help, and hope to hear from people soon. ^_^

I've got 440Gb free on the drive the sims is installed on. Tried Gamebooster, but it had no effect on the choppyness/lag. No changes in frame rate either get a consistent 76-80 fps according to gamebooster.

Yup, I followed the instructions from this page: http://simswiki.info/wiki.php?title=Game_Help:Sims_3_Delete_Cache_Files

Still having choppyness.