3.55v on my -5.0v rail

[Zerileous]

Not sure why, but my -5.0v is really low. I don't think this could be accounted for with resistance. My psu is a FSP AX500-A. The 5.0v rail is 28 amps.
This is just in MBM5, rather than real readings. My other rails are
5.0 is @ 5.00v
3.3 is @ 3.38v
12.0 is @ 11.80v
-12.o is @ -11.85v

I don't know if this is a big deal or not, but it seems like it could be problematic. Any suggestions?

[Peepaw]

I don't think the -5 volt line is used anymore.

[Zerileous]

can anyone confirm this? It would be great if it was just an error/obsolete so I didn't have to worry about this.

[Peepaw]

The different voltage outputs of a PSU are often referred to as "rails". The three main power rails for a modern PSU are +3.3V, +5V and +12V; between them, they'll account for almost all of its power capacity. The next highest rated rail will be the +5VSB (standby) rail, which stays powered up whenever the PSU has mains power; that's what lets your computer power up in response to LAN activity or a space bar press. +5VSB will only account for a few per cent of the total rating, though, and the negative rails (-5V and -12V, which are seldom used for anything in modern PCs) will account for even less.

The above quote is from Dansdata. The last line should answer your question.:)

[Maviryk]

I don't seem to understand how there can be a -5v or even a -12v rail for that matter. Ground is ground....

Maybe S-N can come in here and fill us in, or Oklahoma Wolf.