By Prince McLean

Published: 09:00 AM EST (06:00 AM PST)

Just weeks ahead of its public launch, Apple Inc. has updated the minimum system requirements for its next-generation Leopard operating system to exclude 800MHz PowerPC-based Macs, AppleInsider has learned.

The Cupertino-based company has yet to officially announce the hardware requirements to run Leopard, due out in October, but had long stated in developer documentation that the software would require "an Intel processor or a PowerPC G4 (800MHz or faster) or G5 processor."

According to people familiar with the matter, engineers for the company recently determined that Leopard installs on 800MHz PowerPC G4 systems ran "too slow." Support for those systems was subsequently pulled from the most recent pre-release copies of Leopard, which inform testers that the software "cannot be installed" on those computers.

Instead, Leopard will now require Macs with "an Intel processor or a PowerPC G4 (867 MHz or faster) or G5 processor." Other system requirements include a DVD drive, built-in FireWire, at least 512MB of RAM (additional recommended), and at least 9GB of hard disk space.

Though seemingly mild, the 67MHz increase will exclude a handful of Mac system, namely the 800MHz PowerBook G4 (Titanium), 800MHz PowerMac G4 (Quicksilver), 800MHz iMac G4, 800MHz iBook G4, and 800MHz eMac.

Looking ahead, those people familiar with Apple development cycles speculate that Mac OS X 10.6 will exclude support for PowerPC-based Macs entirely, requiring that users have one of the company's Intel-based systems which first began making their way to market in early 2006.

Over the weekend, Apple provided developers with Mac OS X 10.5 Leopard build 9A559. The build contained only two known issues and is believed to be one of the first candidates for release.