Found on the web - but it could be quite old.

Bryce 7 System Requirements:

Windows

• Pentium Processor (or equivalent) or greater
• 700 MHz (1 GHz or faster recommended)
• Windows 7, Vista, XP, 2000 (SP2+), or NT (SP6)
• 512 MB RAM min (1GB+ recommended)
• 100 MB free hard drive space for installation (500 MB+ recommended)
• OpenGL compatible graphics card with at least 128 MB RAM (Drivers supporting OpenGL 1.1 recommended)
• CD-ROM drive