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What is ErP ready?

The BIOS is something not all of us open frequently, which is exactly why when most people do, they see things they don’t understand. From overclocking controls to power settings, the BIOS can be an intimidating place. 

That said, there are a lot of useful controls buried in there, including important power settings. In this article, we’re looking at ErP-ready ratings and what they mean. 

Also read: How to access BIOS in Windows 11?


ErP Ready explained

ErP, sometimes also labelled EuP is a power management feature in the BIOS that lets the motherboard control power to all system components. This reduces your PC’s overall power consumption by delivering power to output ports only when necessary.

What is ErP ready?
ErP mode controls power consumption by controlling power to system devices, impacting features.

The mode essentially determines whether or not your computer or device can consume less than one watt of energy when in a sleep or shutdown state. Some regulations put this number even lower at only half a watt. 

There are two major reasons why this mode exists:

  • Lower energy consumption: With ErP mode, appliances, including but not limited to computers consume less power. On a larger scale like an office where there are hundreds of computers, each device consuming less power can save massive amounts of electricity and lower the cost for the organisation.
  • Better security: Generally, computer ports continue delivering power in the sleep or sometimes even shutdown modes. In such cases, removing power to the ports essentially kills them, reducing potential points of entry for malicious actors. 

Do remember that ErP mode requires an ErP-ready power supply and compatible motherboard to function.


Different states in ErP mode

The ErP mode essentially controls two states — Shutdown and Sleep/Hibernation. Here’s the difference between the two when ErP is enabled.

Shutdown (S5) stateSleep/Hibernation (S4) state
Power consumptionPower consumption is almost zero.Power consumption is similar to the S5 state.
Software stateA full boot cycle is required to wake up the computer, meaning no software state is saved. The software state is saved so the computer can resume faster.
Hardware latencyHardware requires the boot cycle to be complete to become fully functional.The system can be reverted to an active state by directly interacting with the hardware.
Hardware stateNo hardware state is saved.No hardware state is saved, but the hardware can be called on by an appropriate wake up call.

Unavailable features in ErP mode

Since ErP mode reduces power by controlling power to system components, there are several features that might not work as you’d expect.

  • PME Wake up: With ErP enabled, your system will not be able to boot from a PME or Power Management Event.
  • Wake on LAN: Any boot signals sent over a network (mostly LAN) will not wake a computer.
  • Power on by mouse/keyboard: Depending on your ErP settings, you may or may not be able to wake your PC by moving the mouse or keyboard.

There are pros and cons to using ErP mode. While you’re reducing your overall power consumption and passively enhancing security, that power reduction can also bring along the loss of several features and potential performance impacts. Based on your specific requirements you may want to choose one over the other.

Also read: How to access BIOS in Windows 11?

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