according to speedfan my +12V rail is only 1.09V ,my -12V rail is -16V, and my -5V is -8V. Each of these is well outside the tolerance of a PWR_GOOD signal, and if they were accurate I doubt it would have run for the last four years with these readings.
I might have missed it, but I'm not 100% sure what the BIOS would have to do with this issue, since typically voltage and temperatures are accessed by reading from specific IO addresses. The BIOS can report these values usually too, but typically it's the chipset that actually maps the values from the thermosistors and fan readings to those addresses.
Usually these are the result of faulty hardware monitoring sensors, or (usually more likely) software that doesn't know where to look for the values on that motherboard. Usually it takes a quick look around and makes assumptions about where things are. Sometimes those assumptions are wrong and will give you silly values.
The only thing you can trust is any reading software included in the BIOS itself, since that is designed for the chipset in some fashion. If the voltages are wrong in the CMOS setup screens, than the sensors are busted.
I'd check if my own voltages were caused by ill-inspected sensors but I'm on a 60-day uptime streak. (which I assume would be difficult if my voltages according to speedfan were accurate).
