Strange voltage readings

[_xyz]

are these readings possible, or these are erroneous readings?
if they're possible, which components may be affected from them, and how?

 

[jsc]

The positive readings look OK. The negative readings are clearly erroneous. First of all, in a modern PSU, there is no -5 volt line. Look at your PSU main power connector. You will have one empty pin. That's where a white wire for the -5 volt line would go if you had one.

The -12 volt line is also erroneous. Look in the BIOS for an entry called something like PC Health. That will be pretty accurate. THe -12 volts isn't used much. You can tell from the size of the rail. It's used for analog circuits and RS-232 serial ports.

 

[_xyz]

it reads sometimes less than 3V from the 5V line (the blue line). if it's not wrong, what does it mean?
(the PSU isn't so modern, it's a generic PSU from 5 years ago)
(the MB is GB's 8S661FXM-RZ with IT8712F monitoring chip)

 

[saaiello]

Speedfan is one of the worst to read your voltages i recommend using CPUID HW monitor.

http://cpuid.com/hwmonitor.php

 

[_xyz]