Windows:

Highly Recommended:

OS: 64-bit editions of Windows Vista or newer.
CPU: Intel i5/7/Xeon technology or AMD equivalent.
RAM: 8 GB required for working with multi-million poly models. (16+ GB preferred.)
HDD: 100 GB of free hard drive space for ZBrush and its scratch disk. (SSD drive highly recommended.)
Pen Tablet: Wacom or Wacom compatible. (WinTab API.)
Monitor: 1920×1080 monitor resolution or higher with 32-bit color.
Video card: Most cards manufactured 2008 or newer. Must support OpenGL 3.3 or higher.

OS: 64-bit editions of Windows Vista or newer. (32-bit operating systems are no longer supported.)
CPU: Core2duo or AMD equivalent with SSE2 technology or better.
RAM: 4 GB (6+ GB strongly recommended)
HDD: 8 GB of free hard drive space for ZBrush and its scratch disk.
Pen Tablet: Mouse or Wacom compatible (WinTab API) pen tablet.
Monitor: 1280×1024 monitor resolution with 32-bit color.
Video card: Most cards manufactured 2008 or newer. Must support OpenGL 3.3 or higher.

OS: Mac OS: 10.15 or above.
CPU: Intel i5/7/Xeon technology.
RAM: 8 GB required for working with multi-million polys. (16+ GB preferred.)
HDD: 100GB of free hard drive space ZBrush and its scratch disk. (SSD drive highly recommended.)
Pen Tablet: Wacom or Wacom compatible. (Carbon API.)
Monitor: 1920×1080 monitor resolution or higher with millions of colors.
Video card: Most cards manufactured 2008 or newer. Must support OpenGL 3.3 or higher.

OS: Mac OS: 10.13 or above.
CPU: Core2duo with SSE2 technology or better.
RAM: 4 GB (6+ GB strongly recommended)
HDD: 8 GB of free hard drive space for ZBrush and its scratch disk.
Pen Tablet: Mouse or Wacom compatible (Carbon API) pen tablet.
Monitor: 1280×1024 monitor resolution with millions of colors.
Video card: Most cards manufactured 2008 or newer. Must support OpenGL 3.3 or higher.