Ok, so i have been running Everest's system stability test and PC Wizard 08's global benchmark together. Everest has been running for 42mins now. Through all that testing the +12v never drops below 11.97v. It's the same at idle too!
My 3.3v dropped a bit, 5v dropped too. Is Everest wrong about the +12v line? HWMonitor doesnt even list the 12v line. Im using a Huntkey LW-6400H-3 400W psu, its a budget thing. Any other programs i can use? PC Wiz says its 5v or something lol.
Advice?
My P4 631 is at 3.45GHz, 1.2v with vdrop.

1. You are using a cr@ppy PSU.

2. Voltages reported by software is not usually accurate. Get a multimeter and check out the real voltages. Voltage drops of +/-0.3-0.6 are tipical of low quality PSUs and even some high quality PSUs will have +/- 0.1v or so.

If the PC doesn't crash, BSOD, reboot or shutdown then it doesn't matter what the software is telling you Remember that the official tolerances for the ATX12V standard (which is not just about the +12V rail) indicates a maximum +/-5% on all rails, and +/-10% on the 12V rail under load. I don't like the second tolerance for the 12V rail, as 10.8V doesn't sound like it's going to run much at load

Well it might not exactly crash.

My faulty power supply wasted nearly a week of my time and wrecked two disk drives.

Symptoms were odd disk mis-reads, boot problems, and so on. Diagnostics showed corrupted memory, corrupted disks, faulty motherboard - you name it.

New power supply fixed all those and the machine runs to this day (3 years later).

The power supply tested "marginal" on a dealers test rig.

In future, when I get weird problems like above - I'll reach for my multi-meter.