Is +5VSB necessary when computer is off?

Match

Senior member
May 28, 2001
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I understand it's used to power on the computer. Is it necessary for it to remain on all of the time though? The BIOS chip has a battery, so it doesn't lose information if you pull the plug on the computer. I've read that the +5VSB rail allows you to use features like turning on the computer by hitting a key, using a NIC to bring it out of standby, or using Windows standby mode. I'm trying to figure out if I can turn off the power switch to the surge protector my computer's plugged into, when the computer's not in use for an extended period of time.


Edit: 4/6/05 I'm editing instead of posting and thereby bumping a now dead thread. Thanks for the replies!
 

Matthias99

Diamond Member
Oct 7, 2003
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It's *standby* power. It's there to be used when the system is nominally "off" but still powered, for things like Wake-On-LAN. Note that in "standby" mode, the PSU is still "on", but everything except the CPU/RAM is shut down, and those are put in a low-power mode (so you're not using the +5VSB rail in that case).

Unplugging the computer entirely won't do anything; the BIOS, as noted, has a battery backup. If you unplug it for weeks or months, the BIOS battery may die, but that won't do anything more than resetting the BIOS would do.
 

MrControversial

Senior member
Jan 25, 2005
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You can disable the 5VSB by simply shutting off the power supply via the switch on the back (in the case that your model has one).
 

Zepper

Elite Member
May 1, 2001
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Nothing will be hurt by removing all power from the PC except it may shorten the life of the CMOS/RTC backup battery a bit as a well designed circuit will keep the battery from expending any current when the +5-SB is present.
. You also want to have the +5SB present if you want to use the Wake on Ring, Wake on Keyboard, Wake on ??? features.