whats the difference

Hello, im just reading through motherboard manual, and for the usb and ps2 connectors you can change between 5v and 5vsb

whats the difference?

 

The designation you've asked about may not be standardized -- different manufacturers may use those designations in different ways. I'll tell you how Asus uses the "SB" designation on my motherboard. You get to figure out whether it's applicable to your motherboard.

Using the +5VSB setting on a header keeps 5 volts of power supplied to that header even when the machine has been powered down. It allows you to use the device connected to that header to make the system power itself up. Or maybe other things. You'll likely find some settings in your BIOS's "Power Management" settings that determine what devices you can use on those headers, and what you do with them.

On my machine, I can can power it up with a tap on the spacebar of the keyboard, or with a double left-click. Other options are available. Quite handy if the computer case's power button is in an awkward location.

The Asus "+5VSB" setting requires the +5VSB connection on Pin 9 of the motherboard connector on the power supply. That lead has to be capable of supplying enough current to the motherboard in standby mode. If the lead isn't there, or if there isn't enough current available, the feature doesn't work.