Ever noticed those tiny glowing lights on your motherboard or keyboard even after you’ve shut the computer down for the night? It’s annoying. You’ve clicked "Shut Down," the screen is black, yet your desk looks like a low-budget sci-fi set. This happens because of a specific setting tucked away in your motherboard's brain. Most people ignore it. If you’ve been poking around your UEFI or BIOS settings, you’ve likely stumbled upon something called ErP.
It’s easy to miss.
What is ErP in BIOS? Basically, it is a power-saving feature designed to bring your PC’s energy consumption down to the absolute minimum when the system is "off." Think of it as a deep sleep mode for your hardware. Without it, your PC is a "vampire." It sucks power even when you aren't using it. We’re talking about the Energy-related Products directive. It’s a European Union standard, but it affects hardware sold everywhere from Tokyo to Texas.
The Problem With "Off"
Standard PCs aren't actually off when you shut them down. They sit in a state called S5. In this mode, the motherboard still gets a trickle of power. Why? Because your computer is waiting for a signal. Maybe you want to wake it up via a mouse click, a keyboard press, or a magic packet over the network (Wake-on-LAN).
To keep those features alive, the 5V standby rail on your power supply stays active.
This is where ErP steps in. When you enable ErP in your BIOS, the motherboard cuts off almost all that standby power. It forces the system to consume less than 1 watt—usually under 0.5 watts—of electricity. It sounds like a tiny amount. It is. But over a year, across millions of devices, that’s a massive amount of wasted grid energy.
ErP Ready: What Does It Actually Do?
You might see it labeled as "ErP Ready" or "ErP Lot 6/Lot 9." The terminology depends on whether you're using an ASUS, Gigabyte, MSI, or ASRock board.
When you toggle this to "Enabled," things change.
First, those RGB lights on your RAM or motherboard will finally die. No more rainbow glow at 3 AM. Second, your USB ports will likely lose power. If you usually charge your phone through your PC while it's off, enabling ErP will kill that convenience. The trade-off is efficiency.
Honestly, the "vampire power" draw of a modern PC isn't going to bankrupt you. We're talking maybe $5 to $10 a year in electricity savings for a single home user. But for a business running 500 workstations? That's a different story. That’s a legitimate budget line item.
Why Some People Hate ErP
It isn't all sunshine and lower utility bills. ErP is aggressive.
If you use Wake-on-LAN to access your home office computer from the coffee shop, ErP is your enemy. It shuts down the network card's ability to "listen" for that wake-up signal. The same goes for "Wake on Keyboard." If you like hitting the spacebar to boot your machine instead of reaching down for the power button, you can’t use ErP.
It’s a binary choice. You either want maximum convenience or maximum energy savings. You can't really have both.
I’ve seen plenty of forum posts where users think their motherboard is broken because their mouse stopped glowing. They think the CMOS battery is dying or the PSU is failing. Usually, they just accidentally toggled ErP or bought a board where it was enabled by default to meet environmental regulations.
Compatibility and Hardware Requirements
Not every setup plays nice with ErP. You need a "Ready" power supply.
Most power supply units (PSUs) built in the last decade are ErP Lot 6 compliant. This means they can efficiently handle that sub-0.5W standby draw without whining or causing stability issues. If you’re rocking an ancient PSU from 2008, enabling ErP might cause the system to fail to boot correctly from a cold start.
How to Find the Setting
Finding it is a bit of a scavenger hunt.
- Restart your PC and mash the Delete or F2 key.
- Look for "Advanced" or "Power Management."
- In Gigabyte boards, it's often under the "Power" tab.
- In ASUS boards, look under "APM Configuration" (Advanced Power Management).
You’ll usually see three options: Disabled, Enabled (S4+S5), or Enabled (S5).
S4 is "Hibernation" and S5 is "Soft Off." If you want the most savings, you choose S4+S5. This ensures that whether the computer is hibernating or fully shut down, the power draw stays at rock bottom.
The Nuance of ErP Lot 6 vs. Lot 9
If you’re a real hardware nerd, you’ll notice different "Lot" numbers. These refer to specific tiers of the EU’s ecodesign requirements.
Lot 6 is the standard most of us deal with. It focuses on the standby and off-mode power consumption of electronic and electrical household and office equipment. Lot 9 is newer and more focused on enterprise servers and data storage products. If you see Lot 9 in a consumer BIOS, the manufacturer is basically just bragging that they meet the even stricter server-grade efficiency standards.
Is it Worth Enabling?
Let’s be real. If you’re a gamer with a 1000W power supply and a triple-monitor setup, the 2 watts you save by enabling ErP is a drop in the ocean compared to the 600 watts you pull while playing Cyberpunk 2077.
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However, there is a component longevity argument.
Electromigration and heat are the enemies of electronics. Even a small amount of current running through a motherboard 24/7 generates a tiny amount of heat. Over five or ten years, keeping a system in a true "off" state via ErP could theoretically extend the life of some capacitors. Is there a definitive study proving this adds years to a board? Not really. But in the world of PC building, cooler and "more off" is generally considered better.
Troubleshooting Common ErP Issues
Sometimes ErP causes weirdness.
I’ve encountered systems where enabling ErP caused a "double boot" issue. You press the power button, the fans spin for a second, everything dies, and then it boots up normally three seconds later. This happens because the PSU is taking a moment to stabilize the rails after being completely shut down. It's usually harmless, but it scares people.
Another issue: USB BIOS Flashback. Some high-end motherboards allow you to update the BIOS via a USB stick without a CPU installed. This feature requires standby power. If ErP is enabled, sometimes these "always-on" USB features get wonky. If you're planning on doing heavy firmware maintenance, it's often best to leave ErP off until you're done.
The Verdict on Energy Savings
We have to look at the big picture.
The average PC in standby pulls about 2 to 5 watts.
With ErP enabled, that drops to 0.5 watts.
If your PC is off for 16 hours a day:
- Without ErP: ~29 kWh per year.
- With ErP: ~2.9 kWh per year.
In a place like California or Denmark where electricity is expensive, you’re saving a few bucks. In a dorm room where utilities are included? You probably won't care. But if you hate light pollution in your bedroom or you're trying to build the most "green" PC possible, it's a mandatory toggle.
Actionable Steps for Your Setup
If you want to optimize your power states, don't just stop at ErP.
Start by checking your BIOS for the ErP setting and enable it if you don't need Wake-on-LAN. It’s the cleanest way to shut down those annoying LEDs. While you're in there, check your "CEC Ready" settings if you're on a newer AMD platform—it's a similar California-based energy standard that works alongside ErP.
Next, look at your Windows Power Options. Ensure "Fast Startup" is disabled if you find that ErP is causing your PC to act strangely during boot. Fast Startup is a hybrid hibernation mode that often conflicts with deep-sleep BIOS settings. Disabling it ensures a "clean" shutdown that plays nice with ErP's power-cutting goals.
Finally, invest in a decent surge protector or a PDU with individual switches if you truly want zero draw. Even with ErP, the power supply itself has a tiny bit of internal loss as long as it's plugged into the wall. If you’re leaving for a week, flip the physical switch on the back of the PSU. That is the only 100% effective "ErP mode."
The reality of modern computing is that "off" rarely means off. ErP is the closest the software world gets to actually pulling the plug. It’s a small, technical setting that represents a much larger shift toward hardware accountability. Use it if you want a dark, quiet, and slightly more efficient room. Disable it if you want the convenience of waking your PC from across the house.
Either way, now you know exactly what that cryptic acronym is doing to your motherboard's power delivery.