According to a forum post on Amazon.com, the minimum requirements for the developer's seed of the upcoming Leopard release of OS X lists the following:

• an Intel processor or a PowerPC G4 or G5 processor
• a DVD drive
• built-in FireWire
• at least 256 MB of RAM for a PowerPC based Mac, and 512 MB for an Intel-based Mac
• a built-in display or a display connected to an Apple-supplied video card supported by your computer [The Installer may not support your video card.]
• at least 6 GB of disk space available, or 8 GB if you install the developer tools

Presumably the final minimum requirements would not be that different. However, it's notable that PowerPC G3 processors were included in Tiger's specs, but not in Leopard's. So if these remain as the final minimum requirements, it would mean the first release of OS X that won't run on G3 Macs.

Tags: Macintosh, Apple