-5V on my new GA M61P-S3

[RVC]

Hello all. A couple of questions. I just purchased this mobo and am building a system for my son for Christmas with it. I discovered it needs -5V on pin 20. I have found that many PSUs do not supply this voltage and don't even have a connection at pin 20. This makes me wonder why mobo/PSU advertisements do not include this info that they need/supply this voltage. Does my mobo need this voltage at pin 20 to work properly? What is -5V used for?

 

[RVC]

Thanks to those who read this post. For those who are interested, and for what it's worth, I contacted an engineer with a well known upper echelon power supply company. He said that -5V has not been seriously used on motherboards for 4 or 5 years. It was used in the onboard sound system. He figures my system will work without it. I'll find out tomorrow. Thanks again.

 

[Onus]

The Mushkin 550200 is a 550W PSU on Tier-T of the listing at http://www.xtremesystems.org/forums/showthread.php?t=108088. It has the -5V rail if you need it.
Here's a link: http://www.newegg.com/Product/Product.aspx?Item=N82E16817812002
Note that the specs on Newegg don't list this rail, but if you look at the label, it is there. I have two of these PSUs, and yes, it is there. One of them I got for an Abit board that needs that rail.

 

[RVC]

Thank you. Two of the PC Power and Cooling power supplies also have -5v - the Turbo Cool 510W series and the 300W. None of the other PCP&C do. In fact it's not easy to find a power supply that does provide -5v, which makes me think that not many motherboards need it. I guess my new mobo is an exception. Next time I will pay more attention to this obscure detail.

 

[RVC]

I assembled my new system and used an Antec TruePower 350W power supply without -5V. It booted without any problems and formatted the new HD. But when I tried to install the OS (XP Pro) on the HD the system rebooted serveral times during the last phase of copying files to the HD. Never did figure out why and I was eventually able to completely install the OS without rebooting and now the system runs fine. Perhaps I have an intermitent problem with the power supply.

At any rate, the system seems to run fine without -5V even though there is a -5V pin on the mobo. I have not, however, tried the on-board audio which I was told was what -5V was used for on older boards. Perhaps all this will be helpful, or at least interesting, to someone.

 

[Bohoba]

nice tip to make note of on the MB and sound, now the reboot may have been windows rebooting itself while installing they do have a message that they system may reboot a few times during setup. so that may have been that and not a problem at all.