The FAQ section of the official The Sims site has been updated to include the recommended system requirements for The Sims 4. These are not to be confused with the Minimum System Requirements.
What are the PC recommended system requirements for The Sims 4?
REQUIRED: Internet connection required for product activation.
OS: 64 Bit Windows 7,8, or 8.1
PROCESSOR: Intel core i5 or faster
AMD Athlon X4
MEMORY: 4GB RAM
HARD DRIVE: At least 9 GB of free space with at least 1 GB additional space for custom content and saved games
DVD-ROM: DVD ROM drive required for installation only
VIDEO CARD: NVIDIA GTX 650 or better
SOUND CARD: DirectX 9.0c Compatible
DIRECTX: DirectX 9.0c compatible
INPUT: Keyboard and Mouse