Microsoft KB Archive/131640

= 100% CPU Usage Running SNA Windows 3.x Client on Windows NT =

Article ID: 131640

Article Last Modified on 2/11/2004

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APPLIES TO


 * Microsoft SNA Server 2.0
 * Microsoft SNA Server 2.1
 * Microsoft SNA Server 3.0
 * Microsoft SNA Server 3.0 Service Pack 4
 * Microsoft SNA Server 4.0

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This article was previously published under Q131640



SUMMARY
When you run the SNA Server Windows 3.x client under Windows NT 3.1 or 3.5, Performance Monitor shows CPU utilization at 100 percent. This occurs whenever the SNA Server Windows 3.x client process (WNAP.EXE) is running, even if it is not being used.

The WNAP process, which calls PeekMessage, is causing the Windows NT WOW subsystem to use all available idle CPU cycles. However, due to sophisticated Windows NT process scheduling, other tasks/threads running at a higher priority (including foreground tasks), and tasks/threads running at the same priority, continue to run. You will probably not notice any performance degradation.

The excessive CPU usage does not occur under Windows NT 3.51.



MORE INFORMATION
The high CPU usage occurs on Windows NT 3.1 or 3.5 with any 16-bit Windows application which implements a PeekMessage loop to process Windows messages. The SNA Server Windows 3.x client (WNAP.EXE) uses a PeekMessage loop.

Additional query words: prodsna 2.00 2.10 3.50 CPU

Keywords: KB131640

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