Are you sure you/CPUID are not looking at or reporting the status of one of the 3.3V lines? I ask because, yes, 3V is WAY too low for a 12V line.

So low, that I wouldn't expect your computer be running if it was actually at that voltage. :)

Check out this SU question and answers: How to test a power supply?

It provides some ideas on how to determine if the PSU lines are working and such. Specifically the answers about the PSU tester and using a multi-meter to test the individual lines are probably worth looking into.

Edit:

Also check for updated chipset driver for your motherboard, as the CPUID HW Monitor depends on an SMBus (System Management Bus) driver to interface with the sensors, and many of the SMBus interfaces in the Northwood P4 era were still pretty sketchy.

Are you sure you/CPUID are not looking at or reporting the status of one of the 3.3V lines? I ask because, yes, 3V is WAY too low for a 12V line.

So low, that I wouldn't expect your computer be running if it was actually at that voltage. :)

Check out this SU question and answers: How to test a power supply?

It provides some ideas on how to determine if the PSU lines are working and such. Specifically the answers about the PSU tester and using a multi-meter to test the individual lines are probably worth looking into.

Edit:

Also check for updated chipset driver for your motherboard, as the CPUID HW Monitor depends on an SMBus (System Management Bus) driver to interface with the sensors, and many of the SMBus interfaces in the Northwood P4 era were still pretty sketchy.

Are you sure you/CPUID are not looking at or reporting the status of one of the 3.3V lines? I ask because, yes, 3V is WAY too low for a 12V line.

So low, that I wouldn't expect your computer be running if it was actually at that voltage. :)

Check out this SU question and answers: How to test a power supply?

It provides some ideas on how to determine if the PSU lines are working and such. Specifically the answers about the PSU tester and using a multi-meter to test the individual lines are probably worth looking into.

Are you sure you/CPUID are not looking at or reporting the status of one of the 3.3V lines? I ask because, yes, 3V is WAY too low for a 12V line.

So low, that I wouldn't expect your computer be running if it was actually at that voltage. :)

Check out this SU question and answers: How to test a power supply?

It provides some ideas on how to determine if the PSU lines are working and such. Specifically the answers about the PSU tester and using a multi-meter to test the individual lines are probably worth looking into.

Edit:

Also check for updated chipset driver for your motherboard, as the CPUID HW Monitor depends on an SMBus (System Management Bus) driver to interface with the sensors, and many of the SMBus interfaces in the Northwood P4 era were still pretty sketchy.