Windows Event ID 137 Error The System Firmware has changed the processor's memory type

Windows Event ID 137 Error The System Firmware has changed the processor's memory type range registers (MTRRs) across a sleep state transition (S4).  This can result in reduced resume performance.

Discussion:

This event always happens when the computer goes from sleep to hibernation. The event is not considered worrisome. 

Sleep is a low-power state, but RAM is still active.  Hibernation is a no-power state and it writes RAM to disk and can recover at the same place, even if power is lost.  See more about this, below.

It is a poorly-written event, which should not even be recorded if the machine is going into hibernation.  Of course it will result in slower performance -- that is the definition of hibernation!

Diagnostics:

Windows 10/11 no longer expose the hibernation file in a control panel.  Optionally, and unimportantly, you can look to see if Hibernation is enabled.  It is enabled by default on all Windows installs.

Using File Explorer, on the ribbon bar, click the ellipsis, Options
In Options, click the [View] tab.
Check "[x] Show hidden files, folders, and drives"
Uncheck "[  ] Hide extensions for known file types"
Uncheck "[  ] Hide protected operating system files"
Ignore warnings.
Click OK.

Using File Explorer, browse to the root of the C: drive.
If you have a large file, "hiberfil.sys" -- this is the hibernation file and it is enabled.

Solution:

Consider disabling the hibernation file if you are on a desktop.  Do this especially if a UPS Battery backup is present.  I turn this off on all desktops.

However, if you have a laptop, I do not recommend disabling hibernation.  This feature is used when you close the lid and jump on an airplane.  Laptops will have to accept the Event ID 137.

Disable hibernation steps:

1.  Click Start, type/search "CMD", Run as Administrator
2.  At the DOS Prompt, type this command:

powercfg /hibernate off

You are done.

Note the C:\hiberfile.sys file is deleted.

Related articles:

For other Windows 11 Tuning tips, see
https://keyliner.blogspot.com/2021/11/windows-11-tuning.html

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