System Requirements
Mir renders on the GPU only and requires OpenGL 2.1 to work. The amount of VRAM decides how large of a resolution can be rendered.
The VRAM size requirement is 512MB required and 1GB recommended. Standard Definition compositions may not encounter render errors with 256MB VRAM, but for larger and more complex HD compositions, 512MB-1GB is recommended.
Macintosh
Mac OS 10.6 and 10.7
After Effects CS4, CS5, CS5.5, CS6
Windows
Windows XP, Vista and Windows 7, 32-bit & 64-bit
After Effects CS4, CS5, CS5.5, CS6