PowerSpec G355 Gaming Desktop PC
Windows 10 Pro, Ver. 21H2 (OS Build 19044.2364)
Howdy folks
Since my Desktop has a window to the inside I can see several LEDs that stay on when I shut down.
It's probably NBD, but I've been wondering what needs ongoing power when the computer is off?
TIA for those who take a second to read this post.
Takes time for power to drain outta some components. It used to be a recommendation that if you shutdown your computer from Windows, you shouldn't power up again for 15-20 seconds to avoid power surge/overload (incoming power on top of "undrained" power). Could've been an urban myth, and may not need to be the current practice.
I assume these lights go off eventually.
For your own curiosity, try a hard shutdown (hold on/off button until device turns off) ... same lights stay on ?
The only light that should be on while the computer is turned off is the Standby Power LED.
As @idgat mentioned If you have multiple Lights on still then the PC might not be shutting down completely and is in one of the sleep modes.
if any of the error lights are on(usually red light) or like many lights are on in general then you could have a case short or earth problem.
Hmm, I'm pretty sure they're all on the MB and definitely are yellow.
I'll check just now the specific details and compare again in the morning.
Thanks!
The pushbutton switch that allows the PC to be turned back on is monitored continuously by one part of the mobo that requires power for it to be able to monitor this switch. Wake-On-LAN (WOL) can also be used to power a PC back on after a shutdown, not just to wake the PC from sleep or hibernate, so it consumes a little bit of power too. Typically, this feature can be turned off in the UEFI settings, but doing that doesn't typically prevent the network port from still keep signaling other devices on the same network that the PC still has both ends of its LAN cable plugged in, just not powered on. So, that's why turning off WOL doesn't completely eliminate this power draw. The disco lights (or whatever it is that you prefer to call them) certainly add up to this, but then, most PSUs tend to have piss poor efficiency ratings especially during those times when the PC's power draw is very low, in fact that's when the PSU itself wastes more power than the rest of the whole PC. Although PSU brands like Enermax make PSUs that heavily improve this behavior/style, they're still fairly expensive PSUs (but I like them a lot, Enermax has been making nice quality stuff). The cheapest route is to grab a powerstrip that uses its own power switch so you can just flip the switch. But then you need to put the powerstrip in a spot where you can have convenient access to it, which means more cable spaghetti. Me, I am on a laptop and I use sleep instead of shutting it down. I tried to be someone who likes hibernate. But failed.
A ATX PS has a +5VSB (MB pin 9) that is always on even with the computer off. The PS other sources (3.3V, 5V, 12V and -12V) are switched on and off by a +5VSB return signal from the MB (MB pin 16).
To start and stop the PS (and the computer) the MB connects +5VSB (MB pin 9) to MB pin 16 that switches the 3.3V, 5V, 12V and -12V on and off.
The +5VSB is also used to power memory modules (standby and fast start).
To avoid people to insert or remove the memory modules with the +5VSB on, some MB has a yellow led as an alert "slot is energized, don't touch the memories".
@jdUnionngarden mentioned "several LEDs". A quick look at the MB manual should explain what they are for.
Last edited by Megahertz; 18 Dec 2022 at 17:57.
How to really, shut down a computer...
1. Shut down via case power button or right click START menu.
2. Turn off the switch on the back of the power supply, or shut off the power strip.
3. Hold the case power button, pressed for about 10 seconds, to discharge capacitors.
That's it... you are completely powered off.
Really depends on your computer model and specifics, but basically, the power (stand by) system stays on, just like on your remote control TV. Most if not all computers today use one push button that works on a digital signal basically, there is no on and off state, it's just one temporary contact, and so the system remains monitoring such button, just like hdmi explains here:
Exactly. On remote controlled tvs there is a monitoring system checking for IR commands, but regardless of this, just like on modern computers, such tvs also have one push state power on/off button.
If you really want to turn off your computer (or TV), place a physical button in the middle. This will save you from power consumption and will also protect your system, it's up to you.
Re: ASUS Prime Z390-P Motherboard
I can confirm the flashing LED stays on overnight with my machine powered-down and apparently is a single one, though there is a (reflected) light I can see flashing from the backside of the MB in sync with the one on the top.
The LED is on the end of an empty slot marked "PCIEX16_2".
Perhaps it is there, as @Megahertz mentioned, to alert the connector is hot.
This all may be NBD, but my thanks to all!
Cheers!
PRIME_Z390-P manual
There is a MemOK_II LED on the right side of the ATX power connector near the Dimm A2 socket. (page 1-2 and 1-12)
There is also the LAN port LED indications on the LAN RJ 45 connector on the rear -(outside) of the cabinet. (Page 1-14)
Maybe there are other leds on the Graphics Card and / or Sound Card
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