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Old 10-05-2009, 01:05 PM   #1
Join Date: Jan 2008
Posts: 76
Default Is +5VSB standby power a feature of the "motherboard" or "Power Supply?"


I've been speaking with Gigabyte regarding my 5vsb standby power. I was requesting that they add feature in the BIOS to disable it because my motherboard did not come with jumper settings to disable it.

I was requesting this to be added as a BIOS features because everytime I turn off my computer, my USB devices are kept on and it wastes power. When I shutdown my computer, I want to just click shutdown and leave. Now, I have to wait until it shuts down then crouch under my table to UNPLUG it from my outlet - super annoying. Unpluggin the USB devices are not an option because they are way way back. The outlet is my easiest access.

The support personnel just replied to me and said that they can't add it as a feature because it depends on the PSU NOT the motherboard.

I just want to know if that statement is true because I tried using the PSU to my other gigabyte motherboard (different model) and did not have this problem. USB turns off when shutdown.

BTW, I have a G31m-ES2L rev 1.x

THank you!

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Old 10-05-2009, 08:15 PM   #2
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Default Is +5VSB standby power a feature of the "motherboard" or "Power Supply?"

The power supply will provide stand-by power no matter what (unless it's severely overloaded, or something like that). The ATX standard is dependent on that. It's up to the motherboard to decide what to do with it. There is no requirement for the motherboard to continue supplying power to USB ports when it is turned off.

It may be worth making a realistic estimate of how much power is actually being lost this way, and how much that really bothers you.
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Old 10-05-2009, 09:48 PM   #3
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Location: North Carolina
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Default Is +5VSB standby power a feature of the "motherboard" or "Power Supply?"

Normally they put a jumper on the motherboard to set whether usb devices are powered or not. If not you can't do much about it and a bios setting would require some extra circuitry that would have to of been part of the original design, can't be added as an after thought.

You could buy a hub and use the to disconnect all the devices. If it were me I would probably put a toggle switch on the +5V line of the PSU.
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Old 10-05-2009, 10:03 PM   #4
Join Date: Jan 2008
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Default Is +5VSB standby power a feature of the "motherboard" or "Power Supply?"

I may be exaggerating with the "wasted" power but still .. I feel like I don't want my USB devices turned on all the time. One good example is my 2.5" External hdd (USB power dependent) that keeps on spinning even when the system is off. The drive's lifespan will be less because of this unnecessary spinning.

Thank you both for the information that you gave me, it has been very helpful. I guess the Gigabyte guy is right. Since there are no jumper settings to disable this +5vsb, I have to live with it. What do you expect with a $50 board .. lol.

I'm thinking of modifying it to have a toggle switch, like Modelworks suggested. I'm going to look for parts at Ebay now.

Again, Thanks!

Great forum.
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Old 10-09-2009, 03:38 PM   #5
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Default Is +5VSB standby power a feature of the "motherboard" or "Power Supply?"

If your mobo doesn't have jumpers to disconnect 5vsb from USB and other ports, then there may be a setting in the BIOS setup under Power Up settings, etc. If you have your mobo set to power up from a signal from Mouse, LAN, kbd., etc. then it stands to reason that there has to be 5vsb supplied to those ports. Some mobos have jumpers to supply 5vsb, others may have separate BIOS settings for supplying the power connection.

All ATX PSUs supply some level of 5Vsb to the system, but the mobo controls whether that line is connected to ports while the system is nominally shut down. The 5vsb also keeps the CMOS battery from being drained all the time, so it may not be a good idea to use a PSU's or power strip's on/off switch to totally disable the 5Vsb.

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