By Kasper Jade

Published: 06:00 PM EST

Continuing to refine its recently-released Mac OS X 10.5 Leopard operating system at a rapid pace, Mac maker Apple Inc. will soon begin testing the first pre-release builds of Mac OS X 10.5.2 Update, AppleInsider has learned.

People familiar with the matter say developers could receive an initial test build as early as this week. Mac OS X 10.5.2 will serve as the second maintenance and security update to Leopard since the software went on sale in late October.

Thus far, details of what to expect from the 10.5.2 update are unknown, though rumors published last month by MacBidouille suggested the software was being positioned for a release alongside new hardware at next month's Macworld Expo.

The Mac news and rumor publication cited sources who said the update would be instrumental to the launch of Apple's new Penryn-based 45-nanometer Mac Pro workstations -- the same systems which AppleInsider said earlier this year would clock up to the 3.2GHz via two quad-core Intel "Harpertown" Xeon chips.

MacBidouille said Apple is reworking some of Leopard's codebase via Mac OS X 10.5.2 to optimize it for the SSE4 instructions found within the new Penryn chips and the Penryn architecture as a whole, both of which promise speed gains above and beyond clock speed boosts.

The current version of Leopard is Mac OS X 10.5.1, which was released a little over a month ago. Since then, Apple has begun updating all retail copies of Leopard to include the enhancements and bug fixes delivered by that release.