CPU or Processor Speed Slowdown Errors in Windows Eventlogs


You may receive or notice below warning message in Windows System logs periodically.
Source: Microsoft-Windows-Kernel-Processor-Power
Event ID: 37
Task Category: (7)
Level: Warning
Computer: ServerName
The speed of processor # in group # is being limited by system firmware. The processor has been in this reduced performance state for ## seconds since the last report.”

Starting with Windows Server 2008 R2, CPU power plan has been introduced where we can set the CPU power plan to either balanced or high performance. Each of these power plan has its own advantages and disadvantages. Balanced power plan consumes less power, but when the system or server is very busy, the performance will not be so good. With High performance power plan, the power consumption would be high, but on busy systems it dramatically improves the performance. So, on critical and important busy systems, it is advisable to use high performance CPU power plan. Also, in cases where you notices errors or warnings in event logs as mentioned above, go ahead and enable the high performance CPU power plan.

You can enabled this feature from control panel to either high performance or balanced power plan, but on some systems this may also have been enabled at BIOS level, so you will have to make changes both at control panel and BIOS level. Also on VMware or hyper-v or other virtual systems, it is required that this power plan is set to high performance on both guest and host servers or systems and also at BIOS level on the host server.

Below are the steps to change CPU power plan setting to High performance mode
– Open control panel and check the Power Options. Change or Make sure that the CPU Power Scheme is set to High Performance, and check that every option is set to “Always On”.
– Make sure latest drivers and firmware are installed on the server, especially for your motherboard and CPU.
– Reboot the server or system and go to your BIOS settings. Make sure that your power settings are set to maximum. This may differ from server to server.

Hope this was helpful.

This is applicable for below versions of Windows Servers

Windows Server 2008 R2
Windows Server 2012
Windows Server 2012 R2

SQLServerF1 Team
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