ASCII.jp Modern Standby Compatible PC The mystery of the slider displayed when you click the battery icon

The number of PCs that support "Modern Stanby" is increasing at last.

From around 2019, the number of PCs that support "Modern Standby" has increased. Modern Standby basically always powers on and uses "S0 low power idle" during sleep.

On Modern Standby PCs, there is a "power slider" in the flyout that appears when you click the battery icon in the system tray (notification area).

Older PCs (non-Modern Standby) use ACPI's S3 for sleep. S3 shuts down the PC with the minimum power supply required to maintain the memory and CPU status. On the other hand, "S0 low power idle" turns off the power of many parts of the PC, but the CPU does not stop completely as an idle state with low power consumption. When an interrupt occurs due to receiving a packet from the network, it can be temporarily restored and processed. It stays in a low power state most of the time, which reduces battery consumption and looks like a traditional sleep.

It took a long time to realize this Modern Standby on Windows. Its predecessor, "Connected Standby (Instant ON)," first appeared in Windows 8. However, the basic idea was in the development stage of Windows Vista. However, Vista failed to develop and was based on Windows Server, so there was little improvement in power consumption. It was Windows 8 that made up for that.

However, Connected Standby quickly increased its power consumption due to badly behaved device drivers, etc., and even if it was put to sleep, the battery was steadily reduced. Even if it works on the PC immediately after purchase, the state will be destroyed immediately by connecting the device or installing the application.

Therefore, in Windows 10, a device was added to suppress drivers that are likely to cause problems. For example, changing the network driver. The network driver has a special structure because TCP / IP is processed in the Windows driver, and it is difficult to enable Windows power management. This improvement was previously explained as NetAdapter Cx (NetAdapter Class extensions for WDF) ("The network driver that has been used since the DOS era is finally being improved").

As a result of these long and steady improvements, Modern Standby is finally working properly around 19H1 (Windows10 Ver.1903). The adoption of manufacturers is increasing, and recently, PCs equipped with many 64-bit CPUs are compatible with Modern Standby (32-bit Windows 10 machines using Atom CPUs are compatible with Modern Standby from the beginning).

In addition, on the Internet, we still see stories such as "I want to use / cancel Modern Standby", but Modern Standby is decided by notification from the firmware (UEFI, some people still call it BIOS ...) when installing Windows. In principle, it is an installation option of the manufacturer, and it is quite difficult to enable or disable Modern Standby after purchase, and it can be said that it is impossible for general users. By the way, the Microsoft document also has the following description.

Q: Can I switch between S3 and Modern Standby by changing a setting in the BIOS?

A: No, switching the power model is not supported in Windows without a complete OS re-install. (No, Windows does not support changing the power model without reinstalling the OS.)

https://docs.microsoft.com/en-us/windows-hardware/design/device-experiences/modern-standby-faqs

On Modern Standby compatible models, there is a slider to specify the operation mode in the flyout of the battery icon in the system tray (notification area, right side of the taskbar). This is called the "Performance Power Slider". In Microsoft's Japanese document, it is described as "[Performance] slider", "Performance power slider", and "Power slider". Here, we will use the name "power slider", which is the simplest notation. The introduction has become long, but what's wrong with this power slider?

I checked the operation of the power slider with Powercfg

Windows power management is set with various parameters. However, it is difficult to turn it on / off individually, so all the setting items are put together in a data format called a schema, multiple schemas are created, and this is called a "power plan" so that the settings can be put together. ..

In the era of S3 sleep before Modern Standby, we created multiple power plans and switched between them to decide whether to focus on battery consumption reduction or performance. Modern Standby, on the other hand, has only a "balanced" plan or a manufacturer-specific power plan derived from it. It is possible to make other plans, but it is not recommended.

The power slider is different, and switching doesn't change the power plan. I used the hidden option "/ queryh" in the Powercfg.exe command to switch the power slider and check the schema at that time. For hidden items in Powercfg.exe, please refer to the past article ("Mastering the" Powercfg "command that controls the power relations of Windows machines").

The result was that changing the power slider did not rebel against the power plan, and the schema content remained the same. Well, it doesn't mean that nothing will change. For example, if you set the power slider to "highest performance" on the far right while running on battery, throttling will not be done. Throttling is done at other power slider positions such as high performance, but not always during AC operation. For throttling, see the following article (in "slotling", CPU power management is left to the CPU, not the OS).

The throttling status can be viewed by displaying the "Power Adjustment" column in the "Details tab" of Task Manager. On Modern Standby machines, setting the power slider to "High Performance" will enable "Power Adjustment" for compatible apps, but selecting "Highest Performance" will disable it for all apps.

Also, if you set the power slider to "battery saving", the screen may go dark and some applications (eg OneDrive) may notify you that background operation is restricted.

In other words, changing the power slider is changing the power management of Windows 10, but there is no change in the power plan that shows the parameters.

Previous 12 Next

What is ASCII Club?

Display format: PC ⁄ smartphone