USB power question

maybe a BIOS/UEFI setting, but more likely windows.

a USB device (e.g. keyboard/mouse) may wake the computer from sleep, so the USB controller and root hub (EHCI/XHCI etc) may be kept powered-up to allow that, within device manager you should see "power management" tabs all the way down the USB device tree, where you can tell windows if specific devices are allowed to bring the computer out of sleep, or can be powered-off.

Sometimes these tabs go AWOL.

In the BIOS, there are settings for waking up by mouse or keyboard. Everything on that page turned off. Went to USB power management in Win10 and tried the alternatives - no difference.

Many laptops have two 'types' of USB socket, some which are powered only when the laptop is on and some powered whenever the laptop power is plugged in. Maybe your Gigabyte PC has a similar setup.

Maybe?

YouTube came up with a gigabyte specific video straight away when I entered "turn off powered USB"

Have you also banned yourself from dealing with Google?

:-p

Expand the ?USB settings? and you see, ?USB selective suspend setting? ? This is the default setting for Windows 10. Click on the drop down and select ?Disabled? to not allow Windows power management to suspend or power down the USB port ? Click ?OK? to save setting and close all open Windows.

I generally can't be bothered with videos. Prefer text.

But thanks for the heads up. Turns out you have to enable ERP. Whatever that is. Obviously just me, but I'd expect any such settings to be in the USB section of the BIOS.

ERP is the directive that states how efficient computers should be in in their "off" state. So is the place to find settings for reducing power consumption by disabling USB ports (and other devices) when off.

Is this what was forced on our sovereign nation by the Yanks ?

The whole point though is for that to also be a charger, though I have to say I'm not greatly impressed with their efficiency.

One thing I have also found is that for example, if I use it to power some dongle on my TV, all sorts of crud gets into the supply and power wall warts are better, but don't use the el cheapo ones as they generally buzz or create excessive RFI or both.

As for controlling them on or off. The guy who built my machine said it was a series of jumpers on the mother board, but I never asked him where they actually were, sorry!

Brian

I seem to recall that on many pcs there are two usbs which cannot be powered off as they are for keyboard and mouse so if you put it off, one assumes any attempt to bring it out of deep sleep might not work well if you cannot have the power on. Life used to be so simple in them old days.. sigh. Brian

To support the ATX soft start button and wake-on-LAN features, PCs have long offered a permanent 5V standby supply.

So this USB powering thing is using something that was already there as an independent subsystem. This would be as efficient as a typical plug-in wall adapter (I'd hope).

I don't think stand-by power consumption is part of the ATX or 80 plus standards but the 4 year old PSU driving this post claims less than 0.25 watts.

Ah - thanks for that. Personally. I'd expect to need to enable USB ports being live at all times, rather than it being the default. Doubt many use a desktop to charge their phone. ;-)

Yes.

But if you'd something like an external HD plugged into USB, does it make sense for it to be powered 24/7?

Why not? My mobile lives sat on top of my desktop in the study, it's little use for anything else for me except to receive SMS 2FA messages so that's the obvious place for it!

USB-powered external HDDs will usually enter sleep mode. If your webcam doesn't perhaps that's because it consumes negligible power when not in use. What do the specifications say?

PS I routinely leave my phone charging from a PC overnight when speed is not of the essence.

Why not? <q>

Since all modern 2.5" HDDs are more or less common in their implementation we can use this specification as a reference, but keep in mind that other drives could have deviation up to 20% in comparison to this one (like in question's table).

For archival purposes here is an excerpt from the specification.

Typical power measurements are based on an average of drives tested, under nominal conditions, at 25°C ambient temperature. These power measurements are done with DIPM enabled.

? Spinup current is measured from the time of power-on to the time that the drive spindle reaches operating speed.

? Read/Write current is measured with the heads on track, based on three 64 sector read or write operations every 100 ms.

? The drive supports two idle modes: Active Idle mode and Low Power Idle mode.

?????????????????????????????????????????????????????? ? Power Dissipation ? 5TB, 4TB & 3TB models ? ? ? +5V input average (25° C) ? ?????????????????????????????????????????????????????? ? Spinup (max) ? 1.2A (6W) ? ?????????????????????????????????????????????????????? ? Write average ? 2.10W ? ?????????????????????????????????????????????????????? ? Read average ? 1.90W ? ?????????????????????????????????????????????????????? ? Idle, low power mode ? 0.85W ? ?????????????????????????????????????????????????????? ? Standby/sleep ? 0.18W ? ?????????????????????????????????????????????????????? Standby power is measured at steady state (after 200ms from transition)

from:

Very common in offices, mostly while the machine is running (24/7)

The non-technical think it's a charger socket - its only function. (well, those enamoured by the cool slide-out cup-holder...)

The IT department on the other hand, think it a broken socket & virus security risk, so use can be disabled in BIOS, windows group policy, jumpers, disconnecting wires and hot-melt glue!