Up until now, The Sims 4 has only been available in 32 bit on PC and 64 bit has only been available on Mac.
Great news for all of those with 64 bit systems as you’ll be able to take advantage of a 64 bit version of The Sims 4 in December! Origin will decide which is best for your system and will allow the game to use more than 4gb of memory when it needs to.
The benefits of this? The game will ultimately be more stable and less likely to crash when it exceeds 4gb memory (e.g. on heavily populated lots).
Keep an eye out for the patch, arriving in December (presumably before Get Together launches!).
Great ^^