The Sims 3 Into The Future. Please help!!!

Hi, im chris. Skip the intro.
I'm using windows 8.1 right now. Also, i 've done the run if you can test from your website and i'm 100% sure all the games i passed with flying colours.

I started to install the sims 3 base games and The Sims 3 Island Paradise. I played it so smoothly for two days. But right after i installed the new expansion "The Sims 3 Into the Future", my game started to lag. But the lagginess only started when i meet the Time Traveler professor. After meeting him and chatted to him, my whole games started to lag. 

I've tried many ways. Disabling everything and also download the Game Booster.

Actually it's not really a lag, it's a froze. My game will froze for around 1mins for every 3 mins of gameplay.

PLEASE HELP ME TO SOLVE IT!!!!

And i wanna know why your file is only 3.+gb while others website seemed to be around 6+gb? Please explain this,im blurred.

//EDIT: I had reinstalled my Sims 3. This time, i only installed the Sims 3 base game and The Sims 3 Island Paradise. Surprisingly, my game ran smoothly again like last time. 

Please fix this for me! I really want to play Sims 3 Into The Future!!!!