New
#11
The power comes from the USB port. The fact is that it is a software, BIOS, or UEFI setting that controls it... Not something that is abnormal.
You might want to educate yourself on what USB standby power is. There is a big difference between clicking on shut down in Windows, pressing the power button on the front of the computer, and actually flipping that switch on the back of the computer power supply. If you click on shut down in Windows, or even use the power button on the front of the computer, it is perfectly normal for USB ports to remain powered on most desktop computers manufactured in the past few years. All three of my desktop computers at my house are that way, and hundreds of computers at my workplace are that way.
It's called the S5 system power state.
Wake on LAN works the same way also, the Ethernet controller remains powered on in the S5 system power state if the motherboard fully supports Wake on LAN.
System Power States (Windows)
You also have a good day.
Some motherboards have a BIOS option to supply 5V power to the USB ports for device charging when the PC is off. Check your BIOS to see if there is a setting you can turn off. Note there is always a 5V power supply to the motherboard from the PSU when the PC is off but the PSU is switched on and connected to the mains. I always turn off my PC at the mains switch or PSU switch when not in use (fire risk you know).
There's off and "off" on computers. Full off is when you unplug it from power source but also normal one when you just shut it down either thru OS or by pressing start button.
At normal shutdown most of power is cut to CPU and other parts but there is one wire from PSU to MB that stays live all the time. It's always on at 5v and 0.5 - 2A. It is used to power up computer when you push start button (which is only a momentary switch). MB manufacturers use it to enable charging of devices like phones even when a computer is in OFF state. Some design just some USB ports to have that "always on state" while some give you ability to choose which if any can have that feature thru BIOS settings. My present MB has that last one while earlier one had two USB2 ports at the back to stay always on.
Here's one of schematics for ATX standard PSUs: ATX Power Supply Pinout and Connectors
I have a Standard ATX Power supply with a switch, and when I turn off my PC , I turn off the switch which kills all power to the PC. I do not do that very often but when I place my PC in sleep mode, the RGB lights go off on my mouse and keyboard. I use Corsair equipment and CUE software. But even with the software installed my lights go off and there is no logical reason for them to stay on.
Hi there
Some PC's (Usually or invariably Laptops) have a "Charging Port" on the USB slot - maybe only 1 of several USB ports. HP ones certainly have "This feature" and probably some other makes too.
This will still deliver a charge even when the PC is switched off -- it draws power directly from the internal PC's battery so on these "Charging Ports" you should always remove USB devices if attached to these charging ports.
Standard (non charging) USB ports might be inactive when computer is powered off - in any case I'd always remove any external devices from a laptop after powering it off (possible exception might be a LAN cable).
With Mains type "Servers / desktops" it depends if the PC is in standby or is truely disconnected from the mains -- the 100% way to be sure is to switch the plug off at the mains or pull it out altogether,
Cheers
jimbo