In order for you to play Plants vs. Zombies GOTY Edition on macOS with minimal graphics settings, your computer must meet the following requirements
Operating System:
Mac OS X 10.5.8-10.6.x
Processor (CPU):
Intel Core Duo 1.66GHz+
Memory (RAM):
1GB of RAM
Graphics Card:
64MB of video memory, 16-bit or 32-bit color quality
Hard Drive:
50+MB of free hard drive space
Sound:
Standard audio