A microcode reliability update is available that improves the reliability of systems that use Intel processors. This article describes how to download this update.

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Note The update that is described in this article is not supported on computers that use an older Intel Pentium together with a Family 5 CPU or earlier versions of the CPU. To determine whether the computer uses an older Intel Pentium, follow these steps:

1.	Click Start, right-click My Computer, and then click Properties.
2.	Click Device Manager.
3.	In Device Manager, expand Processors.
4.	Double-click the processor, and then click the Details tab.
5.	Click to select the Hardware Ids in the drop-down list.
6.	Examine the information in the details pane to determine whether the computer uses an older Intel Pentium.

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Frequently asked questions

Q: What issues are fixed by the microcode reliability update?

A: The microcode reliability update fixes the following issues:

•	A possible Intel processor marginality
•	A potential source of unpredictable system behavior
•	A "stop 0x7E" error that may occur during startup on some systems that are running an older Pentium 5 CPU Note This issue occurs only in the 32-bit version of Windows XP and in the x86-based version of Windows Server 2003.

Q: How do you know if the system needs the microcode reliability update?

A: Although these issues are uncommon, you may receive a Stop error, or you may experience unpredictable system behavior.

Q: What errors occur?

A: You may receive a Stop error, or you may experience unpredictable system behavior.

Q: Which Intel processors are affected?

A: Although these issues are uncommon, the following Intel processors may be affected:

•	Mobile: Intel Core 2 Duo mobile processor.
•	Desktop: Intel Core 2 Duo desktop processor, Intel Core 2 Quad desktop processor, and Intel Core 2 Extreme processor.
•	Server: Intel Xeon processors 3000, 3200, 5100, and 5300 series.

Q: If you install the microcode reliability update, do you still require the latest BIOS update?

A: If you install the microcode reliability update, you do not require the latest BIOS update.

Q: Does the microcode reliability update have to be proactively installed?

A: Affected Intel processor users must use the microcode reliability update.

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Update information

The following files are available for download from the Microsoft Download Center:

Update for Windows Server 2003

Download the 32-bit Windows Vista update package now. (http://www.microsoft.com/downloads/details.aspx?FamilyID=eacdfdeb-c1f1-4404-8c50-5d039f5d172d&DisplayLang=en)

Download the 64-bit Windows Vista update package now. (http://www.microsoft.com/downloads/details.aspx?FamilyID=ad3cf1e5-e093-44f0-bbd0-c6e0380dd3f9&DisplayLang=en)

Download the 32-bit Windows Server 2003 update package now. (http://www.microsoft.com/downloads/details.aspx?FamilyID=aad6216c-18a0-450f-8f24-aa1d101bc58d&DisplayLang=en)

Download the 64-bit (x64-based) Windows Server 2003 update package now. (http://www.microsoft.com/downloads/details.aspx?FamilyID=00c39c68-a106-45f0-b886-5831480eee14&DisplayLang=en)

Download the 32-bit Windows XP update package now. (http://www.microsoft.com/downloads/details.aspx?FamilyID=2690495f-c21e-45bc-ae0f-5452b75283d0&DisplayLang=en)

Download the 64-bit (x64-based) Windows XP update package now. (http://www.microsoft.com/downloads/details.aspx?FamilyID=6de7af84-70f0-43ff-ac1f-9bac47b4bcb5&DisplayLang=en)

Release Date: June 11, 2007

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

For more information about the latest service pack for Windows Vista, click the following article number to view the article in the Microsoft Knowledge Base:

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Hotfix information

Prerequisites

No prerequisites are required.

Restart requirement

You must restart the computer after you apply this update.

Hotfix replacement information

This update does not replace any other updates.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista, 32-bit versions

File name	File version	File size	Date	Time	Platform
Update-bf.mum	Not applicable	1,967	24-Apr-2007	19:34	Not applicable
X86_204910432058c231497ea96c24296375_31bf3856ad364e35_6.0.6000.20584_none_e718a75f5a08f4fd.manifest	Not applicable	717	24-Apr-2007	18:16	Not applicable
X86_3b2ff761cd21d25742bf071dbe1f8a18_31bf3856ad364e35_6.0.6000.16474_none_5f9afbbed1d44938.manifest	Not applicable	717	24-Apr-2007	18:16	Not applicable
X86_microsoft-windows-m..update-genuineintel_31bf3856ad364e35_6.0.6000.16474_none_ba921ba3b55bebf8.manifest	Not applicable	3,454	24-Apr-2007	19:34	Not applicable
X86_microsoft-windows-m..update-genuineintel_31bf3856ad364e35_6.0.6000.20584_none_bb10e882ce81a7b3.manifest	Not applicable	3,454	24-Apr-2007	19:34	Not applicable
Mcupdate_genuineintel.dll	6.0.6000.16474	374,456	24-Apr-2007	03:47	x86
Mcupdate_genuineintel.dll	6.0.6000.20584	374,456	24-Apr-2007	02:13	x86

Windows Vista, 64-bit versions

File name	File version	File size	Date	Time	Platform
Amd64_57afb198a18c830bf6e4a856668b78d8_31bf3856ad364e35_6.0.6000.16474_none_c9ce36885899b782.manifest	Not applicable	721	24-Apr-2007	18:16	Not applicable
Amd64_8d5affe835c9b650458335287da11fdb_31bf3856ad364e35_6.0.6000.20584_none_e6642be746cfaddc.manifest	Not applicable	721	24-Apr-2007	18:16	Not applicable
Amd64_microsoft-windows-m..update-genuineintel_31bf3856ad364e35_6.0.6000.16474_none_16b0b7276db95d2e.manifest	Not applicable	3,458	24-Apr-2007	19:39	Not applicable
Amd64_microsoft-windows-m..update-genuineintel_31bf3856ad364e35_6.0.6000.20584_none_172f840686df18e9.manifest	Not applicable	3,458	24-Apr-2007	19:39	Not applicable
Update-bf.mum	Not applicable	1,979	24-Apr-2007	19:34	Not applicable
Mcupdate_genuineintel.dll	6.0.6000.16474	163,512	24-Apr-2007	05:03	x64
Mcupdate_genuineintel.dll	6.0.6000.20584	163,512	24-Apr-2007	03:14	x64

Windows Server 2003, x86-based versions

File name	File version	File size	Date	Time	Platform
Update.sys	5.2.3790.3026	365,056	15-Oct-2007	10:27	x86
Update.sys	5.2.3790.4170	365,056	15-Oct-2007	10:58	x86

Windows Server 2003, x64-based versions

File name	File version	File size	Date	Time	Platform
Update.sys	5.2.3790.2944	152,576	29-May-2007	18:30	x64
Update.sys	5.2.3790.4089	152,576	29-May-2007	18:36	x64

Windows XP, 32-bit versions

File name	File version	File size	Date	Time	Platform
Update.sys	5.1.2600.3218	364,160	19-Sep-2007	10:57	x86

The processor manufacturer may use microcode updates to address errata and to make sure that operational behavior is correct. Windows operating systems include a microcode update mechanism that supports Intel processors. This mechanism lets the operating system apply the latest microcode updates to all processors in the system.

Operating system updates make it possible to apply microcode updates that are later than the versions in the system BIOS. If the processor uses the most recent microcode version, the Windows microcode update mechanism takes no action.

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

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