Microsoft has posted a detailed account of the changes to Windows Vista in the service pack it is scheduled to roll out as a public beta this week..

The 17-page Word document details what Microsoft called "notable changes" in Vista SP1 Release Candidate 1 (RC1), the preview version that has been seeded to thousands of invitation-only testers in recent weeks and soon will be opened to all comers.

Microsoft touted scores of additions, improvements and enhancements to Vista in areas ranging from hardware support and reliability to security and synchronization with the also-upcoming Windows Server 2008.

The "performance and power consumption improvements" category, which sported the largest number of bullet-point items, promised that Vista would copy files locally 25% faster than before and copy files from a remote PC also running Vista SP1 50% faster. Vista SP1 will also read large images faster, and the bundled Internet Explorer 7 has been tweaked so that it renders JavaScript-intensive sites as fast as earlier versions of IE.

On the security front, Vista SP1 includes all the Vista-related security updates issued from the operating system's debut through November, as well as several more general, behind-the-scenes changes. One item in the pack's security improvements list, for example, hints at bug fixes that the company is not calling out as such and won't elucidate. "SP1 includes Secure Development Lifecycle process updates, where Microsoft identifies the root cause of each security bulletin and improves our internal tools to eliminate code patterns that could lead to future vulnerabilities," the document reads.

Microsoft is also making good on a deal it struck over a year ago with Symantec, McAfee and the European Union, which complained before Vista launched that Microsoft was locking down access to the kernel in the 64-bit edition. In the fall of 2006, Symantec and McAfee objected to Microsoft's Kernel Patch Protection, also known as PatchGuard, and claimed that it stymied existing technologies, such as host-based intrusion prevention and tamper prevention. They, along with the EU, also accused Microsoft of using the technology to stifle competition in the security market.

The application programming interfaces that Microsoft first revealed last December are part of SP1, the "change-log" document says. "These APIs have been designed to help security and non-security [independent software vendors] develop software that extends the functionality of the Windows kernel on 64-bit systems, in a documented and supported manner, and without disabling or weakening the protection offered by Kernel Patch Protection," it reads.

The Vista SP1 changes can be viewed as an HTML page or by downloading the Word document.

Vista SP1 RC1 will be offered to user this week via manual download from the Microsoft Web site, but the company has not set a definite date.