This article was previously published under Q163852
This article has been archived. It is offered "as is" and will no longer be updated.
When an Intel processor receives a specific invalid instruction, yourcomputer may stop responding (hang). Your computer must be turned off andrestarted to return to normal operation.
NOTE: Although there is no known operating system or application thatissues such an invalid instruction, you should be aware that a program canbe written maliciously to contain such an instruction. The operating systemwould not trap this error, as it should, which results in the processorhang.
This problem can occur due to an error in the following Intel processors:
Pentium processor with MMX technology
Pentium OverDrive processor
Pentium OverDrive processors with MMX technology
NOTE: This problem cannot occur on the following Intel processors:
Pentium Pro processor
Pentium II processor
i486 and earlier processors
This problem is known as "Invalid Operand with Locked CMPXCHG8BInstruction" and is erratum 81 on the Pentium processor errata list. Formore information, please contact Intel or go to the following Intel website:
Intel has identified a workaround to this problem that allows the operatingsystem to trap the invalid instruction and not pass it to the processor.Microsoft has worked closely with Intel to provide the following hotfixes:
Windows NT 4.0
To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
152734 How to Obtain the Latest Windows NT 4.0 Service Pack
For your convenience, the English version of this post-SP3 hotfix has beenposted to the following Internet location. However, Microsoft recommendsthat you install Windows NT 4.0 Service Pack 4 to correct this problem.
Intel has confirmed this to be a problem in the Intel processors listedabove. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.
Windows NT 3.51
Intel has confirmed this to be a problem in the Intel processors listedabove. A supported fix is now available from Microsoft, but has not beenfully regression-tested and should be applied only to systems experiencingthis specific problem. Unless you are severely impacted by this specificproblem, Microsoft recommends that you wait for the next Service Pack thatcontains this fix. Contact Microsoft Technical Support for moreinformation.
Intel has confirmed this to be a problem in the Intel processors listedabove. Microsoft is researching this problem and will post new informationhere in the Microsoft Knowledge Base as it becomes available.
95 3.50 3.51 4.00 i386 malicious hangs freeze freezes erratum cmpxchg8b compare and exchange 8 bytes cold boot hard
Microsoft Windows NT Server 4.0, Terminal Server Edition, Microsoft Windows NT Workstation 3.5, Microsoft Windows NT Workstation 3.51, Microsoft Windows NT Workstation 4.0 Developer Edition, Microsoft Windows NT Server 3.5, Microsoft Windows NT Server 3.51, Microsoft Windows NT Server 4.0 Standard Edition, Microsoft Windows 95