A reliability and performance update is available for download for Windows Vista Service Pack 1. This specific release targets all Windows Vista editions, provided that they have the first service pack integrated. The update comes with the promise of improving the performance and reliability of Vista SP1, and is not addressed at the RTM SKUs of the latest Windows client. Two updates are available for both the 32-bit and 64-bit versions of Vista SP1. This update resolves issues that may affect some Windows Vista SP1-based computers. These issues have been reported by customers who use the Error Reporting service or Microsoft Customer Support Services.

The current update is designed to tackle performance, responsiveness, and reliability issues affecting Vista SP1 in a variety of scenarios.

According to Microsoft, this update includes the following improvements on a Windows Vista SP1-based computer:

• This update improves the stability of Windows Vista SP1-based computers by addressing some crashes that may occur when you try to check e-mail by using a POP3 e-mail client such as Windows Mail or Mozilla Thunderbird. The crashes may occur on a Windows Vista SP1-based computer in the following scenario incoming POP3 and outgoing SMTP traffic monitoring is enabled.
• Both a third-party antivirus application and an antispyware application are installed, such as the following applications: ZoneAlarm Internet Security Suite by Check Point Software Technologies and SpySweeper by Webroot Software.
• This update improves the reliability of the Windows Vista SP1 based-computers by addressing some problems that occur when you delete user accounts by using the User Accounts item in Control Panel. When this problem occurs, the system may stop responding.
• This update improves the reliability of Windows Vista SP1-based computers that experience issues in which large applications cannot run after the computer is turned on for extended periods of time. For example, when you try to start Excel 2007 after the computer is turned on for extended periods of time, a user may receive an error message that resembles the following:EXCEL.EXE is not a valid Win32 application
• This update improves the reliability of Windows Vista SP1-based computers by reducing the number of crashes that may be caused by the Apple QuickTime thumbnail preview in Windows Live Photo Gallery.
• This update improves the performance of Windows Vista SP1-based computers by reducing audio and video (AV) stuttering. Such AV stuttering may occur when the audio or video component is streaming high definition content from a Windows Vista SP1-based computer that has a NVIDIA network adapter nForce driver version 67.5.4.0 that is installed to a Windows Media Center Extender device.

Download:
Performance and Reliability Update for Vista SP1 (32)
Performance and Reliability Update for Vista SP1 (64)