The Steam page for Mad Max now offers system requirements for Avalanche Studios' upcoming game based on the hard-driving film series (thanks DSOGaming). Currently they indicate the game requires a minimum of 6 GB of RAM:

MINIMUM:
OS: 64 bit: Vista, Win 7, Win 8
Processor: Intel Core i5-650, 3.2 GHz or AMD Phenom II X4 965, 3.4 Ghz
Memory: 6 GB RAM
Graphics: NVIDIA GeForce GTX 660ti (2 GB Memory or higher) or AMD Radeon HD 7870 (2 GB Memory or higher)
DirectX: Version 11
Hard Drive: 32 GB available space

RECOMMENDED:
OS: 64 bit: Win 7 SP1, Win 8.1
Processor: Intel Core i7-3770, 3.4 GHz or AMD FX-8350, 4.0 GHz
Memory: 8 GB RAM
Graphics: NVIDIA GeForce GTX 760 (3 GB Memory or higher) or AMD Radeon HD 7970 (3 GB Memory or higher)
DirectX: Version 11
Hard Drive: 32 GB available space