In order for you to play Total War: WARHAMMER on macOS with minimal graphics settings, your computer must meet the following requirements
Operating System:
macOS 10.12.4 (10.13.6 Recommended)
Processor (CPU):
2.0Ghz Intel Core i5
Memory (RAM):
8 GB RAM
Graphics Card:
2GB Nvidia 680MX, 2GB AMD R9 M290, 1.5GB Intel Iris Graphics 540 or better (see notes for more details)
Storage:
37 GB available space