Program to monitor Power Supply

What symptoms are you having that you think may be related to a PSU issue?

The best way to measure voltages is not with a software program, but rather with a digital multimeter (set to DC volts on the 20V range or automatic) and using a technique called backprobing whereby the probes are inserted into the back of the power connectors so that they make contact with the wires inside. The only software that I would trust on voltage readings is the hardware monitoring in the BIOS (and even then I would take the digital multimeter reading as being the definitive). This is because software that provides this function takes its readings from the on-board sensors and then applies a predetermined offset which gives you the final output reading. Unfortunately, if the incorrect offset is used, it can lead to cases where a voltage is displayed as being out of tolerance whereas the same voltage tested directly is well within the limits.

Certainly, don't stop using these programs if you wish, but remember that the readings that they give should be treated as a guide and that if you have any undue concerns about any of the readings you should confirm (or otherwise) them with a digital multimeter as described above.

Your PSU is from a respectable manufacturer, Corsair, so I wonder if it is actually something else causing the problem. However, we shouldn't totally eliminate it. What model number is it?

It is more likely to be a faulty sensor, or one that is susceptible to changes in temperatures (which would explain why you suspect that you're having these problems under load). Although the BIOS reads its values from sensors, they are not necessarily the same ones that software programs access. However, remember that whilst in the hardware monitoring tab of the BIOS, your system is not under the same load as when the OS is loaded and running.

This is one of those cases where I would definitely recommend the use of a digital multimeter. The voltage reading you quote (3.6V on the 12V line) is simply far too low to allow the computer to remain operating (i.e. I would expect it to cause it to power off). Are you sure this is the 12V line, and not either of the 5V or 3.3V lines?

Good call on removing your overclock. One of the first things to do when experiencing problems is to set everything back to stock/standard settings. It just eliminates one of the possible causes. The same thing, by the way, also applies if you are underclocking.

Do you have access to a digital multimeter? If so, monitor your voltages with TOverclocker as before and then, when the voltage reading dips, check it using the back-probing technique I mentioned earlier. Depending on the voltage you want to check, connect the probes as follows:

Positive/Red probe:

12V - Yellow
5V - Red
3.3V - Orange

Negative/Black probe: Black.

Note that it shouldn't matter which particular wire you choose to probe, but if you want to test multiple (or even all) combinations then feel free to do so.

Do not open up your PSU to do any checking. It can kill you even with the power disconnected.
For most if a PSU is faulty throw it out and buy a new one.

You've already tried multiple programs, and they've all given inconsistent results. In that case, the backprobing technique is the one you should use.

Please heed the above warning: NEVER open the PSU itself.