In order for you to play iO on macOS with minimal graphics settings, your computer must meet the following requirements
Operating System:
OS X 10.6+
Memory (RAM):
2 GB RAM
Graphics Card:
DX9 (shader model 2.0) capabilities
Storage:
250 MB available space
In order to play iO on macOS with maximum graphics settings, you need a computer with a configuration no worse than the following
Operating System:
OS X 10.6+
Memory (RAM):
2 GB RAM
Graphics Card:
DX9 (shader model 2.0) capabilities
Storage:
500 MB available space