Steam now offers minimum and recommended system requirements for Dying Light, and the specs for Techland's action/RPG are as steep as we've ever seen, calling for a minimum of 8 GB of RAM, and recommending 16 GB:

System Requirements

MINIMUM:
OS: Windows® 7 64-bit / Windows® 8 64-bit / Windows® 8.1 64-bit
Processor: Intel® Core™ i5-2500 @3.3 GHz / AMD FX-8320 @3.5 GHz
Memory: 8 GB RAM DDR3
Hard Drive: 40 GB free space
Graphics: NVIDIA® GeForce® GTX 670 / AMD Radeon™ HD 7870
Sound: DirectX® 10

RECOMMENDED:
OS: Windows® 7 64-bit / Windows® 8 64-bit / Windows® 8.1 64-bit
Processor: Intel® Core™ i5-4670K @3.4 GHz / AMD FX-8350 @4.0 GHz
Memory: 16 GB RAM DDR3
Hard Drive: 40 GB free space
Graphics: NVIDIA® GeForce® GTX 780 / AMD Radeon™ R9 290
Sound: DirectX® 10