DICE has revealed the system requirements for Battlefield 4 on the Battlefield Twitter account. Here is what they mean will let you run BF 4 on the PC:

The minimum specs:

OS: Windows Vista SP2 32-bit

CPU: AMD Athlon X2 2,8 GHz

Memory: 4GB

Graphics Card: AMD Radeon 3970HD / Nvidia GeForce 8800GT

Graphics Memory: 512MB

Hard Drive: 30GB

The recommended specs:

OS: Windows 8 64-bit

CPU: AMD Six-Core or Intel Quad-Core

Memory: 8GB

Graphics Card: AMD Radeon 7870HD / Nvidia GeForce GTX660

Graphics Memory: 3GB

Hard Drive: 30GB