Hi, DaniHopkins. Welcome to the forums!
The extra memory will help the game run a little smoother, but there are other bottlenecks in the system that will likely cause some slowdowns. One is the slower video memory in the dedicated graphics chip and the slower hard drive speed. If you can afford it, consider adding a solid state drive along with the expanded memory. As long as you keep the game on medium graphics settings you should be okay, depending on how much expansion/stuff/CC/mods/etc. you have installed.
You mentioned making a Sims 3 miniseries, so I'm assuming you're planning some machinima? You should be okay for recording with keeping the above paragraph in mind. For best results, use something like FRAPS or Bandicam and record to an external hard drive. But I would strongly suggest using a more powerful desktop computer for editing and rendering the episodes.
Hope this helps and happy Simming!
Flynn