Use the software your motherboard came with, or is on the manufacturers site.
Why can people not get this, you see it so often "speedfan is wrong, program x, y or Z is much better". No, they aren't, its really very simple, different mobo's use different chips to monitor the various voltages, the readings from the cpu are incredibly basic to read, but if the software doesn't know which chip is being used to read those voltages, it doesn't know which output is which, its that simple.
If the software doesn't support the monitoring chip, it can't give you ANY proper readings, its not a case of its 11.5v when really its 12.5v, its simply taking readings from the wrong place. IE mobo one has a monitoring chip with pin 1 and 2 reading the difference between 12v and ground, mobo two is using chip 3 and 4, lets say for example sisoft ONLY knows to check pin 1/2 because it doesn't know its a different chip...... its got the wrong reading, simple as.
Sisoft is not a piece of software thats going to be compatible with every mobo out there, monitoring voltages is far from its main programs scope.
Like I said, mobo manufacturers tend to be fairly good at providing accurate readings, 3rd party software is absolute luck, if its had support for your mobo added, or if your mobo is using a chip thats been previously identified.
Its such a utterly simple concept, not all software can read every mobo out there, why would anyone use a 3rd party tool rather than the correct one supplied by their mobo manufacturer.
Now those aren't necessarily 100% accurate, and bugs can happen in any software, but you should get a rough reading thats in the ball park.
Even thats fairly pointless, if you're booting into windows, its fairly obvious you 12v line isn't at 0.81v.
